Packaging coating for shielding high-energy electrons and preparation method and application thereof

Abstract

The invention discloses a packaging coating for shielding high-energy electrons and a preparation method and application thereof, and belongs to the technical field of anti-radiation metal materials. According to the invention, the problem that electronic components are irradiated by high-energy electrons to cause faults in the existing aerospace field is solved. Various metals are mixed to synthesize a high-entropy alloy powder material through a high-energy mechanical alloying technology, epoxy resin is used as a binder to form high-entropy alloy / epoxy resin composite protective coating slurry, the surface of an electronic component is coated with the high-entropy alloy / epoxy resin composite protective coating slurry, and a packaging coating capable of shielding high-energy electrons is obtained. And meanwhile, the problem of poor adhesion between a coating material and a device shell is solved. According to the method, through adjustability of high-entropy alloy elements, by adjusting element types and distortion degrees, by means of the high distortion degrees of the high-entropy alloy, the atomic distance is reduced, the collision probability of electrons in unit cells is increased, maximization of elastic collision and inelastic collision is achieved through coexistence of multi-stage Z elements, and the excellent electronic protection performance is obtained.

Description

Technical Field

[0001] The invention relates to a packaging coating for shielding high-energy electrons and a preparation method and application thereof, belonging to the technical field of radiation-resistant metal materials. Background Art

[0002] With the deepening of space exploration missions, higher requirements are placed on the durability and stability of spacecraft systems. Electronic components are important components of spacecraft power supply, communication, navigation and other systems. Therefore, the life of electronic components determines whether the space system can operate normally. However, electronic components are affected by the total dose effect of high-energy electrons in the space environment, causing their performance to degrade or even fail. Therefore, developing an efficient method to improve the radiation resistance of electronic components has become a research hotspot in the field of space protection.

[0003] The existing technology has two methods for protecting electronic devices from the total dose effect of high-energy electrons: active protection and passive protection. Passive protection achieves the purpose of protection by blocking radiation through materials, and has the advantages of strong initiative, strong design, and wide material selectivity. The research and development and application of protective coatings can extend the service life of devices in radiation environments, and is an effective means to solve the total dose effect. The material thickness is controllable, the molding method is flexible, and the composition can be adjusted in a large space. Among them, metal coatings have excellent radiation protection capabilities as radiation protection coatings, but they are difficult to process and have poor integration with devices. Compared with metal coatings, polymer-based coatings have the advantages of strong adhesion, excellent insulation, light weight, and lower price, and are a radiation protection material for electronic devices with great potential.

[0004] The protective performance of polymer-based composite coatings is determined by functional fillers. High entropy alloys have the characteristics of easy adjustment of crystal structure, designable element composition, and excellent radiation shielding performance, which provide unique opportunities for the structural design of functional fillers. According to the design principles of high entropy alloy materials such as atomic radius, valence electrons, and electronegativity differences, high entropy alloys can be divided into Cantor alloys, Senkov alloys, and low-density alloys. Considering the element selection from the perspective of electronic protection, high atomic numbers (Z) such as Mo, Ta, and W in Senkov alloys contribute to the elastic and inelastic scattering of electron nuclei. Adding low-Z elements such as Al and Cr to the alloy can not only increase the inelastic scattering of extranuclear electrons, but also reduce the density of high entropy alloys. Due to the objective differences in atomic size and electronegativity of graded Z metal components, high entropy alloys are prone to large lattice distortion. The lattice distortion effect is used to adjust the local electronic structure of the nucleus and the material, thereby enhancing the dissipation of radiation energy. Therefore, the use of high entropy alloy / epoxy resin composite coatings as high-energy electronic protective coatings for electronic components is of great significance for the development of radiation protection materials for space exploration. Summary of the invention

[0005] In order to solve the problem of failure of electronic components caused by high-energy electron irradiation in the existing aerospace field, the present invention provides a packaging coating for shielding high-energy electrons, a preparation method and an application thereof.

[0006] The technical solution of the present invention:

[0007] One of the purposes of the present invention is to provide a packaging coating for shielding high-energy electrons, and the packaging coating specifically comprises high-entropy alloy powder and a resin matrix;

[0008] The high entropy alloy powder is composed of a base metal powder and an added metal powder; the base metal powder includes tantalum powder, tungsten powder, niobium powder and molybdenum powder; the added metal powder is titanium powder, vanadium powder, chromium powder or aluminum powder.

[0009] It is further defined that the molar ratio of tantalum powder, tungsten powder, niobium powder and molybdenum powder in the base metal powder is 1:1:1:1.

[0010] It is further defined that the amount of the additional metal powder added is 0 to 20% of the mass of the base metal powder.

[0011] It is further defined that the mass proportion of the high entropy alloy powder in the packaging coating is 5 to 50%.

[0012] It is further defined that the resin matrix is ​​an epoxy resin adhesive.

[0013] The second object of the present invention is to provide a method for preparing the above-mentioned packaging coating for shielding high-energy electrons, the method comprising the following steps:

[0014] (1) mixing the base metal powder and the added metal powder in proportion, placing the mixture in a ball mill, adding zirconium oxide balls for ball milling, and obtaining a high entropy alloy powder;

[0015] (2) High entropy alloy powder and resin matrix are mixed in proportion, placed in a three-roll grinder for thorough grinding and mixing to obtain a slurry, the slurry is coated on the matrix, and placed in a vacuum oven for drying to obtain a packaging coating for shielding high-energy electrons.

[0016] It is further defined that the ball-to-material ratio in (1) is (1-40):1, the ball milling speed is 200-1000 r / min, and the time is 5-50 h.

[0017] It is further defined that the slurry coating thickness in (2) is 0.1 to 2 mm.

[0018] It is further defined that the vacuum drying temperature in (2) is 30 to 100° C. and the time is 6 to 8 hours.

[0019] The third object of the present invention is to provide an application of the above-mentioned packaging coating in high-energy electron radiation protection.

[0020] Beneficial effects:

[0021] The present invention mixes multiple metals and synthesizes high entropy alloy powder material through high-energy mechanical alloying technology, uses epoxy resin as a binder, forms a high entropy alloy / epoxy resin composite protective coating slurry, and applies it on the surface of electronic components to obtain a packaging coating with shielding high-energy electrons, while solving the problem of poor adhesion between the coating material and the device housing. Compared with the prior art, the present invention also has the following advantages:

[0022] (1) The present invention adjusts the element types of high entropy alloy materials to achieve graded Z element matching and high entropy lattice distortion in the lattice of the material, thereby increasing the collision probability of high-energy electrons and materials, thereby increasing the shielding performance of high-energy electrons. Among them, Al, Ti, V, and Cr elements can not only form high entropy alloys with NbMoTaW, but also due to the objective differences in atomic size and electronegativity of graded Z metal components, high entropy alloys are more likely to have larger lattice distortion. Lattice distortion is closely related to the atomic size and bond length of HEA, and is caused by the chemical interaction between the constituent elements. The local electronic structure of the nucleus and the material can be effectively adjusted through lattice distortion. The principle of electronic protection is based on the interaction between electrons and atomic nuclei and extranuclear electrons. The increase in local atomic nucleus density is achieved through lattice contraction, thereby increasing the collision probability between the atomic nucleus and the incident electron, thereby enhancing the electron energy dissipation.

[0023] (2) The present invention utilizes the excellent bonding and simple implementation characteristics of the polymer-based composite coating, and can be directly coated on the surface of electronic components to encapsulate and reinforce the electronic components, thereby improving the radiation resistance of the device.

[0024] (3) The present invention utilizes the adjustability of high entropy alloy elements, adjusts the element types and distortion, utilizes the high distortion of high entropy alloys to reduce the atomic distance, increases the collision probability of electrons in the unit cell, and utilizes the coexistence of multiple levels of Z elements to maximize elastic and inelastic collisions, thereby obtaining excellent electronic protection performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Cr prepared in Example 1 10％ XRD pattern of NbMoTaW high entropy alloy powder;

[0026] Figure 2 Ti prepared in Example 2 10％ XRD pattern of NbMoTaW high entropy alloy powder;

[0027] Figure 3 Cr prepared in Example 4 10％ XRD pattern of NbMoTaW high entropy alloy powder;

[0028] Figure 4 Cr prepared in Example 1 10％ SEM image of NbMoTaW high entropy alloy powder;

[0029] Figure 5 Ti prepared in Example 2 10％ SEM image of NbMoTaW high entropy alloy powder;

[0030] Figure 6 The shielding dose of the encapsulation coating prepared in Examples 1 to 5 against 500 krad and 1 MeV electrons;

[0031] Figure 7 Output curves of electronic components encapsulated by the encapsulation coating prepared in Example 1 before and after electron irradiation;

[0032] Figure 8 The transfer curve of the electronic components encapsulated by the encapsulation coating prepared in Example 1 before and after electron irradiation;

[0033] Fig. 9 DFT calculation of crystal parameters for the high entropy alloy prepared in Example 1. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0035] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0036] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0037] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained through commercial channels by those skilled in the art.

[0038] Example 1

[0039] (1) Preparation of high entropy alloy powder:

[0040] Tantalum powder, tungsten powder, niobium powder and molybdenum powder were mixed in equal molar ratio, 10wt.% chromium powder was added, the mixture was uniformly used as ball milling material, placed in a ball milling jar, zirconium oxide balls were added, the ball-to-material ratio was 20:1, argon gas was introduced as protective gas for 5 minutes, ball milling was performed, the ball milling speed was 600rpm, the ball milling time was 24h, after the ball milling was completed, the ball-to-material was separated, the powder was placed in a vacuum drying oven, and dried at 60℃ for 6h to obtain Cr 10％ NbMoTaW high entropy alloy powder.

[0041] (2) Preparation of encapsulation coating:

[0042] According to the proportion of high entropy alloy powder of 10wt.%, the high entropy alloy powder was mixed with the resin matrix (Kraft K-9761 transparent epoxy resin AB glue, the mass ratio of A glue to B glue was 2:1), and fully ground and mixed using a three-roll grinder for 5 minutes. After grinding, the obtained slurry was coated on the surface of the device, and then placed in a vacuum drying oven and dried at 30°C for 6 hours. Repeat the coating-drying process until the coating thickness reaches 1mm to obtain a packaging coating.

[0043] Example 2

[0044] (1) Preparation of high entropy alloy powder:

[0045] Tantalum powder, tungsten powder, niobium powder and molybdenum powder in equal molar ratios were mixed, and 10wt.% titanium powder was added. The mixture was uniformly mixed as a ball milling material, placed in a ball milling jar, and zirconium oxide balls were added. The ball-to-material ratio was 20:1. Argon gas was introduced as a protective gas for 5 minutes and then ball milling was performed. The ball milling speed was 600rpm and the ball milling time was 24h. After the ball milling was completed, the ball and material were separated, and the powder was placed in a vacuum drying oven and dried at 60°C for 6h to obtain Ti 10％ NbMoTaW high entropy alloy powder.

[0046] (2) Preparation of encapsulation coating:

[0047] According to the proportion of high entropy alloy powder of 10wt.%, the high entropy alloy powder was mixed with the resin matrix (Kraft K-9761 transparent epoxy resin AB glue, the mass ratio of A glue to B glue was 2:1), and fully ground and mixed using a three-roll grinder for 5 minutes. After grinding, the obtained slurry was coated on the surface of the device, and then placed in a vacuum drying oven and dried at 30°C for 6 hours. Repeat the coating-drying process until the coating thickness reaches 1mm to obtain a packaging coating.

[0048] Example 3

[0049] (1) Preparation of high entropy alloy powder:

[0050] Tantalum powder, tungsten powder, niobium powder and molybdenum powder in equal molar ratios were mixed, 20wt.% chromium powder was added, the mixture was uniformly used as ball milling material, placed in a ball milling jar, zirconium oxide balls were added, the ball-to-material ratio was 20:1, argon gas was introduced as protective gas for 5 minutes, ball milling was performed, the ball milling speed was 600rpm, the ball milling time was 24h, after the ball milling was completed, the ball-to-material was separated, the powder was placed in a vacuum drying oven, and dried at 60℃ for 6h to obtain Cr 20％ NbMoTaW high entropy alloy powder.

[0051] (2) Preparation of encapsulation coating:

[0052] According to the proportion of high entropy alloy powder of 10wt.%, the high entropy alloy powder was mixed with the resin matrix (Kraft K-9761 transparent epoxy resin AB glue, the mass ratio of A glue to B glue was 2:1), and fully ground and mixed using a three-roll grinder for 5 minutes. After grinding, the obtained slurry was coated on the surface of the device, and then placed in a vacuum drying oven and dried at 30°C for 6 hours. Repeat the coating-drying process until the coating thickness reaches 1mm to obtain a packaging coating.

[0053] Example 4

[0054] (1) Preparation of high entropy alloy powder:

[0055] Tantalum powder, tungsten powder, niobium powder and molybdenum powder were mixed in equal molar ratio, 10wt.% chromium powder was added, the mixture was uniformly used as ball milling material, placed in a ball milling jar, zirconium oxide balls were added, the ball-to-material ratio was 5:1, argon gas was introduced as protective gas for 5min, ball milling was performed, the ball milling speed was 600rpm, the ball milling time was 24h, after the ball milling was completed, the ball-to-material was separated, the powder was placed in a vacuum drying oven, and dried at 60℃ for 6h to obtain Cr 10％ NbMoTaW high entropy alloy powder.

[0056] (2) Preparation of encapsulation coating:

[0057] According to the proportion of high entropy alloy powder of 10wt.%, the high entropy alloy powder was mixed with the resin matrix (Kraft K-9761 transparent epoxy resin AB glue, the mass ratio of A glue to B glue was 2:1), and fully ground and mixed using a three-roll grinder for 5 minutes. After grinding, the obtained slurry was coated on the surface of the device, and then placed in a vacuum drying oven and dried at 30°C for 6 hours. Repeat the coating-drying process until the coating thickness reaches 1mm to obtain a packaging coating.

[0058] Comparative Example 1

[0059] The difference between this comparative example and Example 1 is that the amount of chromium powder added is 0, and the remaining process steps and parameter settings are the same as those in Example 1, to obtain NbMoTaW high entropy alloy powder.

[0060] Effect example

[0061] (1) XRD characterization was performed on the high entropy alloy powders prepared in Example 1, Example 2 and Example 4. The results are as follows: Figure 1 to Figure 3 As shown in the figure, it can be seen that when the ball-to-material ratio is 5:1, some metals are not completely alloyed due to insufficient ball milling energy, and the material is in a multiphase mixed state; when the ball-to-material ratio is 20:1, all metals are completely dissolved to form a single high-entropy alloy solid solution.

[0062] (2) The microscopic morphology of the high entropy alloy powders prepared in Example 1 and Example 2 was characterized, and the SEM photos were as follows: Figure 4 and Figure 5 As shown in the figure, it can be seen that under the action of high-energy ball milling, all metal elements are evenly dispersed and multi-phase is generated without segregation.

[0063] (3) The high-energy electron shielding performance of the encapsulation coatings prepared in Examples 1 to 4 was simulated and tested. The results are as follows: Figure 6 As shown by Figure 6 It can be seen that the encapsulation coating prepared in Example 1 has the best shielding effect on 1MeV electrons.

[0064] (4) The radiation resistance of the packaged electronic device was tested. The electrical parameters of the packaged electronic device in Example 1 were tested before and after irradiation with high-energy electrons (500 krad, energy of 1 MeV). The test results are as follows: Figure 7 and Figure 8 shown.

[0065] First, the Cr with a thickness of 1 mm was tested 10％ - Output curve of MOSFET device under HEA / EP composite coating, such as Figure 7 As shown in the figure. After irradiation, the Ids of the bare MOSFET device increases, indicating that the MOSFET device changes from the off state to the on state. This phenomenon is caused by the increase in the amount of charge captured in the dielectric layer when electrons bombard the MOSFET device. 10％ -HEA / EP packaged MOSFET devices have significantly lower Ids, which confirms that Cr 10％ -HEA / EP package MOSFET reliability under electron irradiation has been significantly improved. The threshold voltage directly affects the switching speed, power consumption and performance of MOSFET devices. Figure 8 Shows Cr 10％-Transfer curve of MOSFET device encapsulated with HEA / EP composite coating. Under high-energy electron radiation, the negative displacement curve of MOSFET device along the voltage axis can be observed. The results show that the voltage of bare MOSFET device drops from 3.66V to -0.49V. Cr 10％ -HEA / EP package MOSFET device voltage dropped from 3.66V to 3.40V, the test results show that Cr 10％ Devices packaged in NbMoTaW / EP have excellent radiation resistance.

[0066] (5) DFT was used to analyze the Cr 10％ The first principle calculations of the NbMoTaW high entropy alloy powder and the NbMoTaW high entropy alloy powder obtained in Comparative Example 1 are as follows: Fig. 9 As shown, the addition of Cr leads to a decrease in the lattice parameter and a contraction of the lattice.

[0067] Although the present invention has been disclosed as above in the preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A packaging coating for shielding high-energy electrons, characterized in that: including high entropy alloy powder and resin matrix; The high entropy alloy powder is composed of a base metal powder and an added metal powder; the base metal powder includes tantalum powder, tungsten powder, niobium powder and molybdenum powder; the added metal powder is titanium powder, vanadium powder, chromium powder or aluminum powder.

2. The encapsulation coating according to claim 1, characterized in that The molar ratio of tantalum powder, tungsten powder, niobium powder and molybdenum powder in the base metal powder is 1:1:1:

1.

3. The encapsulation coating according to claim 1, characterized in that The amount of the added metal powder is 0 to 20% of the mass of the base metal powder.

4. The encapsulation coating according to claim 1, characterized in that: The mass proportion of high entropy alloy powder in the packaging coating is 5 to 50%.

5. The encapsulation coating according to claim 1, characterized in that: The resin matrix is ​​an epoxy resin adhesive.

6. A method for preparing a packaging coating for shielding high-energy electrons according to any one of claims 1 to 5, characterized in that: include: (1) mixing the base metal powder and the added metal powder in proportion, placing the mixture in a ball mill, adding zirconium oxide balls for ball milling, and obtaining a high entropy alloy powder; (2) High entropy alloy powder and resin matrix are mixed in proportion, placed in a three-roll grinder for thorough grinding and mixing to obtain a slurry, the slurry is coated on the matrix, and placed in a vacuum oven for drying to obtain a packaging coating for shielding high-energy electrons.

7. The preparation method according to claim 6, characterized in that: (1) The ball-to-material ratio is (1-40):1, the ball milling speed is 200-1000 r / min, and the time is 5-50 h.

8. The preparation method according to claim 6, characterized in that: (2) The coating thickness of the medium slurry is 0.1 to 2 mm.

9. The preparation method according to claim 6, characterized in that: (2) The vacuum drying temperature is 30-100°C and the time is 6-8 hours.

10. Use of the encapsulation coating according to any one of claims 1 to 6 in high energy electron radiation protection.

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