CN113881312B - Rare earth-high Z-graphene-composite coating for aerospace-grade chip total dose effect protection and preparation method thereof - Google Patents
Rare earth-high Z-graphene-composite coating for aerospace-grade chip total dose effect protection and preparation method thereof Download PDFInfo
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- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
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Abstract
A rare earth-high Z-graphene-composite coating for aerospace-level chip total dose effect protection and a preparation method thereof belong to the technical field of radiation protection. The invention aims to solve the technical problem that the existing space total dose effect resistant protective material is single in performance. The invention is composed of functional filler and resin matrix. The functional filler is composed of graphene nano coils with rare earth metal oxides and high-Z materials directionally distributed on the surfaces, then the graphene nano coils are mixed with a resin matrix, and the mixture is coated on the surface of an aerospace-grade chip by utilizing an ultrasonic-assisted thermal spraying device and is cured and formed in a segmented mode. The invention can effectively improve the overall total dose effect irradiation performance of the composite coating and effectively prevent the coating and the substrate from being degraded and degraded by irradiation.
Description
Technical Field
The invention belongs to the technical field of radiation protection, and particularly relates to a rare earth-high Z-graphene-composite coating for aerospace-grade chip total dose effect protection and a preparation method thereof.
Background
The total dose effect refers to the degradation of device performance caused by radiation induced trapped charges in the oxide layer. For aerospace devices, particularly aerospace chips, radiation not only generates trapped charges and interface state charges in gate oxide, but also generates in other media such as field isolation oxide layers and buried oxide layers. These radiation-induced charges can cause device off-state leakage and increased edge leakage, resulting in increased static power consumption and even functional failure of the integrated circuit. Therefore, only by solving the problem of total dose hardening resistance of the chip, the barrier can be eliminated for aerospace-level application of the chip technology, and the chip can be better applied to a microelectronic product with radiation hardening resistance.
Disclosure of Invention
Most rare earth elements belong to heavy metal elements, the shielding effect on gamma rays is more obvious than that of low-Z elements such as boron, in addition, the rare earth elements have special atomic structures and have the advantage of making up a weak absorption region of lead, the areas of n and gamma reaction sections of the rare earth elements on thermal neutrons are dozens of times higher than that of boron, and the areas of the n and gamma reaction sections of the rare earth elements on thermal neutrons are also dozens of times higher than that of boron. The design and preparation of the rare earth radiation-proof material become the research focus of the radiation-proof material due to a plurality of advantages. Graphene is a new two-dimensional carbon material, and has more excellent physical, chemical and mechanical properties compared with the traditional carbon material. In addition, the graphene has excellent conductivity, can resist electron irradiation to a certain extent, has a higher scattering cross section and a low absorption cross section for neutrons, and is an excellent neutron moderator. The graphene nano roll is formed by rolling single-layer or multi-layer two-dimensional planar graphene and has an open structure. In addition to having high mechanical strength, high thermal conductivity and high electrical conductivity, electron transport occurs throughout the system due to unusual electrical and optical properties.
Aiming at the existing research results, the invention provides a rare earth-high Z-graphene-composite coating for aerospace-level chip total dose effect protection and a preparation method thereof. After the composite material is dispersed in the resin matrix, a multilayer alternating structure is formed on the microstructure, so that the process for preparing the multilayer alternating material is simplified, and the material has better shielding capability of electrons, neutrons and gamma rays.
The invention aims to solve the technical problem of single performance of the existing space total dose effect resistant protective material, and provides a rare earth-high Z-graphene-composite coating for aerospace-grade chip total dose effect protection and a preparation method thereof.
The technical scheme of the invention is as follows:
the rare earth-high Z-graphene-composite coating for the total dose effect protection of the aerospace-grade chip consists of a functional filler and a resin matrix. The functional filler is composed of graphene nano rolls with rare earth metal oxides and high-Z materials directionally arranged on the surfaces, wherein the functional filler accounts for 10-50% of the composite coating by mass. The method comprises the following specific steps: step one, rare earth is mixedMetal oxide, high-Z metal material and ZrO2ZrO is put together with the grinding balls2In a ball milling tank with an inner liner, after a cover is covered, high-purity argon (with the mass concentration of 99.99%) is introduced through two gas filling holes reserved on a tank cover to thoroughly exhaust air, the ball milling tank is fixed in a ball mill, the ball mill is operated after parameters are set to start ball milling, the tank is opened periodically in the ball milling process to check, when materials are stuck or caked, the caked materials are crushed and stripped from the tank body, carrier gas is refilled to continue ball milling, after the ball milling is finished, the ball milling tank is cooled to the room temperature, a sample is taken out to prevent the sample from being oxidized due to contact with air at the high temperature, the prepared sample is taken out to be stored in a sealed mode (such as being put into a sample bag) for later use, and a composite powder material is obtained;
step two, dissolving 0.25g of graphene nanocolloid into 200mL of ethylene glycol, and performing ultrasonic oscillation for 15min to obtain a uniform graphene dispersion liquid; adding 1.0g of the composite powder material prepared in the first step, continuing ultrasonic oscillation for 15min, refluxing at a high temperature of 180 ℃ for 24h, filtering, washing with absolute ethyl alcohol for 3-5 times, then washing with deionized water for 3-5 times, and then drying in a vacuum drying oven at 60 ℃ for 12 h.
Further, the mass ratio of the rare earth metal oxide to the high-Z metal material is (1-5): 1.
Further defined, the rare earth oxide is one or a combination of more of gadolinium oxide, europium oxide, praseodymium oxide, dysprosium oxide and erbium oxide in any ratio.
Further defined, the high-Z material is one or a combination of tungsten, tantalum and bismuth in any ratio.
Further limit, the ball-material ratio is (2-8):1, the rotation speed of the ball mill is 200rpm-1000rpm, and the ball milling time is 12h-48 h.
Further, the graphene nanocolloid is prepared by a freeze-drying method, and specifically, the preparation method comprises the following steps:
firstly, centrifugally washing graphene until the pH value of the solution is neutral, and then freeze-drying at-20-0 ℃ to obtain graphene sponge;
then adding the graphene dispersion liquid into deionized water, and performing ultrasonic dispersion for 30min-60min to obtain graphene dispersion liquid with the concentration of 0.005mg/mL-0.1 mg/mL;
then dropwise adding 1mL of the graphene nano-roll onto a clean glass sheet or a clean silicon sheet, horizontally placing the glass sheet or the silicon sheet in vacuum equipment, pumping the glass sheet or the silicon sheet until the vacuum degree is 1Pa-20Pa, performing vacuum treatment at normal temperature to quickly evaporate water, and controlling the vacuum treatment time to be 10min-30min to obtain the graphene nano-roll;
further, the resin material is any one of epoxy resin, cyanate ester, polyurethane and high-density polyethylene.
The preparation method of the graphene roll/rare earth composite coating is characterized by comprising the following steps:
and mixing the functional filler with the resin matrix, grinding for 5-10 min by using a three-roll grinder to obtain slurry, coating the slurry on the surface of the aerospace-grade chip, placing the aerospace-grade chip in a vacuum drying oven, and drying for 6-8 h at the temperature of 30-100 ℃ to obtain the aerospace-grade chip.
Further limiting, the thickness of the coating is 100 um-1 cm;
further limiting, the coating method is selected from spray coating, knife coating and the like.
The invention has the following beneficial effects:
gd in the functional filler of the invention2O3the/W can be directionally arranged on the surface of the graphene nano roll, and the graphene nano roll is used as an electron acceptor to promote electrons to be emitted from organic resin and Gd2O3the/W interface is transferred to the graphene roll to provide a rapid transmission channel for charges, so that the components show a good synergistic effect at the interface through a charge transfer process, the overall electron irradiation resistance of the composite coating can be effectively improved, and the degradation and performance degradation effects of the electron irradiation on the coating and the substrate are effectively prevented.
Gd of the present invention2O3the/W @ GNSs functional filler plays an obvious role in reinforcing the resin matrix. The method not only can effectively inhibit the generation and the propagation of microcracks in an interface area, but also can absorb free radicals generated by irradiation, thereby reducing the degradation of resin, and finally, the irradiation resistance of the resin coating can be greatly improved through the synergistic effect.
The invention adopts epoxy resin as the resin material. The epoxy resin structure contains a plurality of groups, wherein the epoxy group has higher chemical activity and can carry out ring-opening reaction in the presence of a curing agent to form a three-dimensional network structure; the rigid structure of the benzene ring can provide certain mechanical strength and friction resistance for the cured resin. In addition, the epoxy resin has higher density and stronger tolerance to radiation, can block fast radiation particles and effectively shield the irradiation of the total dose effect.
Drawings
Fig. 1 is a TEM photograph of graphene nanocolloids with rare earth oxide and high z arranged in an oriented manner.
Detailed Description
The following examples describe embodiments of the invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagent or the apparatus is not specified by the manufacturer, and is a conventional product which can be obtained by commercial purchase.
Embodiment mode 1:
step one, preparing graphene nano roll by freeze-drying method
Firstly, centrifugally washing graphene until the pH value of the solution is neutral, then freeze-drying at-20 ℃ to obtain graphene sponge, adding deionized water, and ultrasonically dispersing for 60min to obtain 0.01mg/mL graphene dispersion liquid; and then dropwise adding 1mL of the graphene nano roll onto a clean silicon wafer, horizontally placing the silicon wafer in vacuum equipment, pumping until the vacuum degree is 10Pa, performing vacuum treatment at normal temperature to quickly evaporate water, wherein the vacuum treatment time is 10min, and thus obtaining the uniformly curled graphene nano roll.
Step two, preparing the rare earth metal oxide/high Z composite material by a ball milling method
Weighing a rare earth metal oxide material and a high-Z metal material according to the mass ratio of 1:1, wherein the rare earth metal oxide is gadolinium oxide, and the high-Z metal material is tungsten.
Then, ZrO with the diameter of 1mm is weighed according to the ball-to-material ratio of 2:12ZrO is put together with the grinding balls2In the ball milling tank with the lining, the ball milling tank is utilized after being covered by a coverTwo reserved air charging holes on the tank cover adopt high-purity argon (99.99%) for 10min to thoroughly exhaust air, finally the ball milling tank is fixed in a ball mill, and the ball mill is operated for 12h after the rotation speed is set to be 400 rpm. And opening the pot regularly during the ball milling process for inspection, when the materials are stuck or agglomerated, crushing the agglomerated materials, stripping the pot body, then refilling high-purity argon (99.99%) into the pot body, continuing ball milling, cooling the ball milling pot to room temperature after the ball milling is finished, taking out the sample, and taking out the prepared sample to be placed into a sample bag for later use in order to prevent the sample from being oxidized due to contact with air at high temperature.
Step three, preparing graphene nanocolloid/rare earth/high-Z functional filler
Weighing 0.25g of the graphene nanocolloid prepared in the step one, dissolving the graphene nanocolloid into 200mL of ethylene glycol solution, and carrying out ultrasonic oscillation for 15min to fully dissolve the graphene nanocolloid so as to obtain uniform graphene dispersion liquid; and (3) adding a certain amount of the composite split material prepared in the second step into the mixture, and continuing to perform ultrasonic oscillation for 15min to fully mix the two. The mixture was refluxed at a high temperature of 180 ℃ for 24 hours, the resulting product was filtered, washed 3 times with anhydrous ethanol and then with deionized water for 3 times, and then placed in a vacuum drying oven for 12 hours.
Step four, preparing the irradiation protective coating
And (3) according to the fact that the powder accounts for 10% of the total mass of the composite coating, mixing a certain amount of the functional filler prepared in the third step with the epoxy resin matrix, fully grinding and mixing the functional filler and the epoxy resin matrix by using a three-roll grinder, wherein the grinding time can be controlled to be 10min according to the content of the powder, and after the grinding is finished, spraying the mixed slurry on the surface of the aerospace-grade chip to form a coating with the thickness of 100 um. And (3) placing the coating in a vacuum drying oven, and drying for 6 hours at the temperature of 30 ℃.
And (3) testing the radiation protection performance: using the above-mentioned coating in241Am radiation source, in which241The Am source energy was 60 Kev. The results are given in the following table:
TABLE 1
As can be seen from the table, the coating was on241The linear attenuation coefficient 12.332 under the Am source is only 0.181cm when the linear attenuation coefficient is attenuated to one tenth of the original value, and the radiation of the total dose effect can be effectively resisted.
Claims (7)
1. The rare earth-high Z-graphene-composite coating for the total dose effect protection of the aerospace-grade chip is characterized in that the composite coating is composed of a functional filler and a resin matrix, wherein the functional filler is a graphene nano-coil with rare earth oxide and high Z materials directionally arranged on the surface, and the functional filler accounts for 10-50% of the mass fraction of the composite coating; the preparation method of the functional filler comprises the following steps:
step one, rare earth oxide, high Z material and ZrO2ZrO is put together with the grinding balls 2In the ball milling tank with the lining, after the cover is covered, high-purity argon is introduced through two gas filling holes reserved on the tank cover to remove air in the ball milling tank, the ball milling tank is fixed in a ball mill, the ball mill is operated to start ball milling after parameters are set, and after the ball milling is finished, the ball milling tank is cooled to room temperature and then is taken out and sealed for storage, so that a composite powder material is obtained;
step two, dissolving 0.25g of graphene nanocolloid into 200mL of ethylene glycol, and performing ultrasonic oscillation for 15min to obtain a uniform graphene dispersion liquid; adding 1.0g of the composite powder material prepared in the step one, continuing ultrasonic oscillation for 15min, refluxing at a high temperature of 180 ℃ for 24h, filtering, washing with absolute ethyl alcohol and deionized water in sequence, and then drying in a vacuum drying oven at 60 ℃ for 12 h;
the rare earth oxide is gadolinium oxide, the high-Z material is tungsten, and the resin material of the resin matrix is epoxy resin.
2. The composite coating according to claim 1, wherein the mass ratio of the rare earth oxide to the high-Z material is (1-5): 1.
3. The composite coating of claim 1, wherein the ball-to-material ratio of step one is (2-8):1, the rotation speed of the ball mill is 200rpm to 1000rpm, and the ball milling time is 12h to 48 h.
4. The composite coating of claim 1, wherein the graphene nanocoils are prepared by a freeze-drying process; the method is specifically completed by the following steps:
firstly, centrifugally washing graphene until the pH value of the solution is neutral, and then freeze-drying at-20-0 ℃ to obtain graphene sponge;
then adding the graphene dispersion liquid into deionized water, and performing ultrasonic dispersion for 30min-60min to obtain graphene dispersion liquid with the concentration of 0.005mg/mL-0.1 mg/mL;
and then dropwise adding 1mL of the graphene nano roll onto a clean glass sheet or a clean silicon sheet, horizontally placing the glass sheet or the silicon sheet in vacuum equipment, pumping until the vacuum degree is 1Pa-20Pa, performing vacuum treatment at normal temperature to quickly evaporate water, and controlling the vacuum treatment time to be 10min-30min to obtain the graphene nano roll.
5. The method for preparing a composite coating according to any one of claims 1 to 4, wherein the preparation method is carried out by the following steps:
mixing the functional filler with the resin matrix, grinding for 5-10 min by using a three-roll grinder to obtain slurry, coating the slurry on the surface of a protected object, placing the protected object in a vacuum drying oven, and drying for 6-8 h at the temperature of 30-100 ℃ to obtain the composite material.
6. The method for preparing a composite coating according to claim 5, wherein the coating thickness is 100 μm to 1 cm.
7. The method for preparing the composite coating according to claim 5, wherein the coating method is selected from a spray coating method and a blade coating method.
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