Preparation method of ionizing radiation shielding material

Abstract

The invention discloses a preparation method of an ionizing radiation shielding material. The method specifically comprises the following steps: calculating the mixing enthalpy of a plurality of high-entropy compounds according to a density functional theory so as to screen out alternative high-entropy compounds meeting a preset mixing enthalpy criterion; simulating and predicting the ionizing radiation shielding performance of the alternative high-entropy compound according to Monte Carlo radiation transfer so as to screen out an alternative mixed material meeting a preset shielding performance standard; and preparing the ionizing radiation shielding material according to the alternative mixed material. According to the method, the complete process of screening, predicting and preparing can be achieved in the mode that DFT calculation and MC simulation are combined, and the number of times of experiment trial and error is reduced in the mode that preparation is conducted after mixed enthalpy and performance simulation two-layer screening is conducted on multiple different high-entropy compound metal components at the same time; therefore, the energy consumption and the time consumption of the ionizing radiation shielding material are reduced, and meanwhile, the alternative high-entropy compound can be ensured to have single-phase stability and large-scale synthesis by taking the mixing enthalpy as a constraint.

Description

TECHNICAL FIELD

[0001] The application relates to a method for preparing an ionizing radiation shielding material, and belongs to the technical field of material science. BACKGROUND

[0002] At present, ionizing radiation shielding materials prepared by using single fillers such as tungsten oxide and bismuth oxide are increasingly widely applied in nuclear energy, aerospace and medical radiation protection, but the shielding efficiency of the above materials is still lower than that of lead-based materials. When tungsten, bismuth, gadolinium and other elements are used as the core and a plurality of metal elements with shielding potential are selected to form a stable single-phase high-entropy structure powder to prepare an ionizing radiation shielding material, different components need to be synthesized one by one and the phase stability and performance need to be verified, which is easily affected by process fluctuations and consumes a large amount of energy and time. Moreover, after the powder design is completed, the matching and structure optimization between the powder and the matrix need to be considered before the specific device is constructed, which requires a large number of trial and error experiments and consumes a large amount of energy and time. In addition, the sintering time required by the high-temperature sintering technology in the related art is also long. The above three factors are superimposed, which results in large energy consumption and time consumption in the preparation process of the ionizing radiation shielding material. SUMMARY

[0003] The application is proposed to solve the above problems, and further provides a method for preparing an ionizing radiation shielding material.

[0004] The method for preparing an ionizing radiation shielding material in the application embodiment comprises the following steps: calculating the mixing enthalpy of a plurality of high-entropy compounds according to the density functional theory to screen out candidate high-entropy compounds meeting a preset mixing enthalpy criterion; predicting the ionizing radiation shielding performance of the candidate high-entropy compounds according to the Monte Carlo radiation transmission simulation to screen out candidate mixed materials meeting a preset shielding performance standard; manufacturing the ionizing radiation shielding material according to the candidate mixed materials.

[0005] Further, the metal elements in the candidate high-entropy compound include two of a plurality of optional metal elements and a plurality of candidate metal elements, the optional metal elements include bismuth, tungsten and gadolinium, the candidate metal elements include lanthanum, samarium, cerium, yttrium and zirconium, and the molar ratio of the metal elements included in the candidate high-entropy compound is the same.

[0006] Further, the step of calculating the mixing enthalpy of a plurality of high-entropy compounds according to the density functional theory to screen out candidate high-entropy compounds meeting a preset mixing enthalpy criterion comprises: constructing a special quasi-random structure model according to the density functional theory; Based on the special quasi-random structure model, the mixing enthalpy of a plurality of high-entropy compounds is calculated. The high-entropy compound with a mixing enthalpy between -15 kJ / mol and +5 kJ / mol is determined as the alternative high-entropy compound.

[0007] Further, the ionizing radiation shielding performance of the alternative high-entropy compound is predicted according to the Monte Carlo radiation transport simulation to screen out an alternative mixed material meeting a preset shielding performance standard, comprising: The ionizing radiation shielding performance of a target mixed material is predicted according to the Monte Carlo radiation transport simulation to screen out the alternative mixed material, wherein the target mixed material comprises the alternative high-entropy compound and a matrix material, the matrix material being polypropylene, epoxy resin, polyurethane or rubber, and the mass ratio of the high-entropy compound in the target mixed material being between 20% and 70%.

[0008] Further, the ionizing radiation shielding performance of the target mixed material is predicted according to the Monte Carlo radiation transport simulation to screen out the alternative mixed material, comprising: According to the Monte Carlo radiation transport simulation, the linear attenuation coefficient, the half-value layer parameter, the tenth-value layer parameter or the radiation protection efficiency of the target mixed material is predicted in a preset energy range. Based on the preset shielding performance standard, the alternative mixed material is screened out from the target mixed material according to the linear attenuation coefficient, the half-value layer parameter, the tenth-value layer parameter or the radiation protection efficiency.

[0009] Further, the ionizing radiation shielding material is made according to the alternative mixed material, comprising: According to the alternative mixed material, a corresponding alternative metal source and a complexing agent are uniformly mixed, and a precursor corresponding to the alternative mixed material and in a gel or film shape is made in a preset temperature range; or According to the alternative mixed material, a corresponding alternative metal source and a complexing agent are uniformly mixed, and a precursor in a powder shape corresponding to the alternative mixed material is made by co-precipitation or spray drying; Based on pulse or direct current heating of a conductive mold, the electric resistance heating of the precursor placed in the conductive mold is performed at a preset heating rate and peak temperature, and holding is performed in a first preset time range. The cooled precursor is cooled to make the ionizing radiation shielding material.

[0010] Further, the alternative metal source comprises a nitrate or an acetate, the complexing agent comprises citric acid or ethylene glycol, the preset temperature range is 100-220 DEG C, the temperature rising rate ranges from 100-300 DEG C / s, the peak temperature ranges from 600-1400 DEG C, and the first preset time range is 5-20 s.

[0011] Further, the method further comprises: mixing and smelting the ionizing radiation shielding material with a base resin under a molten or solution condition, and preparing a target sample with a preset thickness through hot pressing or extrusion-pressing; measuring the ionizing radiation shielding performance of the target sample within a preset energy range, and comparing and checking the ionizing radiation shielding performance of the target sample with the ionizing radiation shielding performance of the alternative mixed material, so as to adjust the alternative mixed material according to the checking result.

[0012] Further, the measuring the ionizing radiation shielding performance of the target sample within a preset energy range, and comparing and checking the ionizing radiation shielding performance of the target sample with the ionizing radiation shielding performance of the alternative mixed material, so as to adjust the alternative mixed material according to the checking result, comprises: performing a gamma ray transmittance test on the target sample within the preset energy range, so as to obtain the linear attenuation coefficient of the target sample; performing the comparison and checking and adjusting the alternative mixed material according to the linear attenuation coefficient of the target sample, so that the linear attenuation coefficient of the target sample in the energy region of 662 keV is 20% higher than the linear attenuation coefficient of a preset sample filled with bismuth oxide or tungsten oxide in the energy region of 662 keV.

[0013] Further, the method further comprises: testing the oxidation resistance of the target sample by using an oxidation induction time method; performing a tensile property test on the target sample according to a preset standard.

[0014] The application has the beneficial effects that: the application can realize a complete preparation process of screening-prediction-preparation by combining density functional theory calculation with Monte Carlo radiation transport simulation, can greatly reduce the number of experimental trial and error by performing preparation after two-layer screening of mixed enthalpy and performance simulation of multiple different high-entropy compound metal components, thereby reducing energy consumption and time consumption of ionizing radiation shielding materials, and can also ensure that the alternative high-entropy compound has single-phase stability and scale synthesis by taking mixed enthalpy as a constraint. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1Figure 1 is a flowchart of a method for preparing an ionizing radiation shielding material according to an embodiment of the present application; Figure 2 Figure 2 is a flowchart of a method for preparing an ionizing radiation shielding material according to another embodiment of the present application; Figure 3 Figure 3 is a schematic diagram of a microstructure of an ionizing radiation shielding material according to an embodiment of the present application; Figure 4 Figure 4 is a flowchart of a method for preparing an ionizing radiation shielding material according to another embodiment of the present application; Figure 5 Figure 5 is a flowchart of a method for preparing an ionizing radiation shielding material according to another embodiment of the present application; Figure 6 Figure 6 is a flowchart of a method for preparing an ionizing radiation shielding material according to another embodiment of the present application; Figure 7 Figure 7 is a flowchart of a method for preparing an ionizing radiation shielding material according to another embodiment of the present application; Figure 8 Figure 8 is a flowchart of a method for preparing an ionizing radiation shielding material according to another embodiment of the present application; Figure 9 Figure 9 is a schematic diagram of a test result of a gamma ray transmittance test according to an embodiment of the present application; Figure 10 Figure 10 is a schematic diagram of a test result of a gamma ray transmittance test according to another embodiment of the present application; Figure 11 Figure 11 is a schematic diagram of a test result of a gamma ray transmittance test according to another embodiment of the present application; Figure 12 Figure 12 is a flowchart of a method for preparing an ionizing radiation shielding material according to another embodiment of the present application. DETAILED DESCRIPTION

[0016] Referring to Figure 1 The method for preparing an ionizing radiation shielding material according to an embodiment of the present application specifically includes the following steps: Step 01: Calculate the mixing enthalpy of a plurality of high-entropy compound combinations according to the density functional theory, to screen out a candidate high-entropy compound combination that meets a preset mixing enthalpy criterion.

[0017] Specifically, the method for preparing an ionizing radiation shielding material according to an embodiment of the present application, before actually performing the material preparation step, pre-screens the ionizing radiation shielding material by using the density functional theory (DFT), to screen out a high-entropy compound combination that is thermodynamically synthesizable.

[0018] The high-entropy compound combination is generally a high-entropy oxide, a high-entropy carbide or a high-entropy boride of multiple metal elements, and the metal elements are divided into two parts, i.e., a necessary metal element and an optional metal element according to the radiation shielding mechanism, wherein the necessary metal element is generally bismuth, tungsten and gadolinium, and the optional metal element includes lanthanum, samarium, cerium, yttrium and zirconium. The high-entropy compound combination generally includes five metal elements to form a five-metal system, which includes all the necessary metal elements and two of the five optional metal elements. In this way, the two-by-two combination of the optional metal elements can form 10 metal element combination modes.

[0019] In addition, in actual application, the number of metal elements in the metal system formed can be adjusted according to actual conditions, and accordingly, the number of optional metal elements selected can also be adjusted according to actual conditions.

[0020] The molar ratio of the cations of the metal elements in the five-metal system can be adjusted according to actual conditions. For example, the molar ratio of the cations of the metal elements can be controlled to be the same, such as a high-entropy oxide (Bi 0.2 W 0.2 Gd 0.2 La 0.2 Sm 0.2 )O2, wherein the molar ratio of bismuth, tungsten, gadolinium, lanthanum and samarium elements is the same, and 1 mol of the high-entropy compound contains 0.2 mol of Bi, 0.2 mol of W, 0.2 mol of Gd, 0.2 mol of La and 0.2 mol of Sm.

[0021] In addition, for example, the high-entropy oxide can be divided into a high-entropy fluorite oxide (FHEOs, (M1M2M3M4M5)O2), a high-entropy spinel oxide (SHEOs, (M1M2M3M4M5)2O4) and a high-entropy perovskite oxide (PHEOs, (M1M2M3M4M5)O3) according to the different molar ratios of the metal elements and oxygen elements, wherein M1-M5 are the metal elements in the five-metal system.

[0022] Please refer to Figure 2 , and the screening method of the high-entropy compound combination involved in step 01 is as follows Step 011: constructing a special quasi-random structure model according to the density functional theory.

[0023] Specifically, on the basis of the above-mentioned embodiments, the screening method of the high-entropy compound combination is based on the calculation of mixing enthalpy by density functional theory, so the method proposed in the embodiments of the application is first based on the calculation of density functional theory (DFT) to construct a special quasi-random structure (SQS) model, and further uses the special quasi-random structure model to calculate the mixing enthalpy of a plurality of high-entropy compound combinations. Before calculation, the selection of metal elements in the high-entropy compound combination can be performed in advance, that is, two of the five optional metal elements are selected on the basis of the three mandatory metal elements, and then the selected two optional metal elements and the three mandatory metal elements are jointly used as the metal element combination in the high-entropy compound combination, so as to facilitate subsequent calculation of each metal element combination by the SQS model.

[0024] Step 012: Calculate the mixing enthalpy of a plurality of high-entropy compound combinations based on the special quasi-random structure model.

[0025] Specifically, on the basis of the above-mentioned embodiments, in the case of constructing the special quasi-random structure (SQS) model based on the calculation of density functional theory (DFT), the SQS model is used to calculate the mixing enthalpy of each high-entropy compound combination with preselected metal elements, so as to subsequently screen the high-entropy compound combinations with synthesizability based on the mixing enthalpy as the standard. Specifically, the above-mentioned SQS model is based on the plane wave pseudopotential method (Plane-Wave Pseudopotential Method, PWPP) to perform the calculation of mixing enthalpy by first principles, and the specific calculation method can be adjusted according to the actual situation, which is not limited in the application.

[0026] Step 013: Determine the high-entropy compound combination with the mixing enthalpy between -15 kJ / mol and +5 kJ / mol as the optional high-entropy compound.

[0027] Specifically, on the basis of the above-mentioned embodiments, the generated SQS model is used to calculate the mixing enthalpy of each high-entropy compound combination with preselected metal elements, respectively, to obtain the corresponding mixing enthalpy calculation results, and a preset mixing enthalpy range is used as a standard to screen the high-entropy compound combinations, specifically, the high-entropy compound combinations with the corresponding mixing enthalpy calculation results falling within the preset mixing enthalpy range are retained, and the high-entropy compound combinations with the corresponding mixing enthalpy calculation results not within the mixing enthalpy range are discarded.

[0028] For example, the above-mentioned enthalpy of mixing is generally set to -15kJ / mol to +5kJ / mol. High-entropy compound combinations with enthalpy of mixing within the above range are retained, while high-entropy compound combinations with enthalpy of mixing outside the above range are discarded. For example, based on the above implementation method, if the required metal elements are bismuth, tungsten, and gadolinium, and two of the five candidate metal elements (lanthanum, samarium, cerium, yttrium, and zirconium) are selected to form a high-entropy oxide, the mixing enthalpy calculation using the SQS model shows that the mixing enthalpy of the high-entropy oxide formed by bismuth, tungsten, gadolinium, lanthanum, and samarium falls within the aforementioned mixing enthalpy range, while the mixing enthalpy of the high-entropy oxide formed by bismuth, tungsten, gadolinium, lanthanum, and zirconium does not. Therefore, the high-entropy oxide formed by bismuth, tungsten, gadolinium, lanthanum, and samarium is identified as a candidate high-entropy oxide, while the high-entropy oxide formed by bismuth, tungsten, gadolinium, lanthanum, and zirconium cannot be identified as a candidate high-entropy oxide. Please refer to further details. Figure 3 , Figure 3 The diagram shows the overall microstructure of the ionizing radiation shielding material actually obtained after the high-entropy oxide material is prepared based on five metallic elements: bismuth, tungsten, gadolinium, lanthanum, and samarium. It also shows partial microstructure diagrams of the six elements, including the five metallic elements and oxygen.

[0029] In this way, the method provided in this application can use the SQS model built based on density functional theory (DFT) to screen out the synthetically viable candidate high-entropy oxides from a variety of high-entropy compound combinations directly before the actual preparation of materials by prioritizing the calculation of mixing entropy and the preset mixing entropy range, thereby significantly reducing the energy consumption and time consumption of the preparation process.

[0030] Please continue reading. Figure 1 The method for preparing ionizing radiation shielding material in the embodiments of this application further includes: Step 02: Predict the ionizing radiation shielding performance of the candidate high-entropy compounds based on Monte Carlo radiative transfer simulation (MC) to screen out candidate hybrid materials that meet the preset shielding performance criteria.

[0031] Specifically, after screening for synthesizable candidate high-entropy oxides, it is necessary to further predict their ionizing radiation performance to select potential candidate high-entropy oxides with better ionizing radiation shielding performance. This can effectively narrow down the range of selectable high-entropy oxides, thereby significantly reducing the energy and time consumption of the preparation process. Therefore, by way of example, the method in this application uses Monte Carlo radiative transfer simulation (MC) to predict the ionizing radiation shielding performance of the screened candidate high-entropy oxides.

[0032] Further, please refer to Figure 4The prediction method for ionizing radiation shielding performance involved in step 02 specifically includes the following steps: 021: Based on Monte Carlo radiative transfer simulation, the ionizing radiation shielding performance of the target hybrid material is predicted in order to screen candidate hybrid materials. The target mixture includes candidate high-entropy compounds and matrix materials. The matrix materials are polypropylene, epoxy resin, polyurethane, or rubber. The mass ratio of high-entropy compounds in the target mixture is between 20% and 70%.

[0033] For example, based on the above embodiments, since high-entropy oxides need to be mixed with other matrix materials to form composite materials in practical applications, when further predicting the ionizing radiation shielding performance of candidate high-entropy compounds, the prediction object needs to be set as a mixture of candidate high-entropy compounds and matrix materials. Because the ionizing radiation shielding performance of the candidate high-entropy compounds themselves, their mass ratio in the mixture with the matrix materials also affects the overall ionizing radiation shielding performance of the mixture. Therefore, before performing MC to predict the ionizing radiation shielding performance of the target mixture, it is necessary to pre-set the mass ratio of candidate high-entropy compounds to matrix materials in the target mixture. Only then can MC be used to predict the ionizing radiation shielding performance corresponding to each ratio, thereby screening out the target mixture with the best potential ionizing radiation shielding performance as a candidate mixture.

[0034] In addition to ionizing radiation shielding performance, the mechanical properties, thermal stability, oxidation resistance and processability of the target hybrid material also need to meet the requirements. Therefore, in the target hybrid material, the mass ratio of the candidate high-entropy compound is generally between 20% and 70%. After experimental verification, when all the above properties can be taken into account as much as possible, the mass ratio of the candidate high-entropy compound is generally between 40% and 60%.

[0035] Therefore, before performing the MC prediction, multiple allocation values ​​can be selected from the aforementioned mass proportions, such as a value every 5% or every 10%. During the MC prediction process, ionizing radiation shielding performance prediction is performed separately for each target mixture with different candidate high-entropy compound mass proportions. After calculations are completed for each target mixture, the target mixture corresponding to the optimal prediction result is selected as a candidate mixture and used as a reference standard for subsequent material preparation. It is important to note that the prediction accuracy of the software platform used to perform the MC prediction should be greater than or equal to 95%, for example, the FLUKA software platform can be used to perform the MC prediction.

[0036] Please see Figure 5 Furthermore, step 021 also includes: Step 0211: Based on Monte Carlo radiative transfer simulation, predict the linear attenuation coefficient, half-value layer parameter, tenth-value layer parameter, and / or radiation protection efficiency of the target hybrid material within a preset energy range.

[0037] Specifically, based on the above implementation method, the process of performing MC simulation generally involves performing prediction calculations for each target hybrid material at multiple different energy values ​​within a preset energy range, in order to obtain one or more parameter values ​​that can reflect the ionizing radiation shielding performance of the target hybrid material.

[0038] Specifically, the preset energy range is generally 59.5 keV to 1332 keV. Within this range, the four energy regions of 59.5, 662, 1173, and 1332 keV are highly representative. When performing MC prediction, calculations can be performed in the four energy regions mentioned above. In addition, specific energy regions can be selected for additional MC prediction calculations as needed. This application does not impose any specific limitations.

[0039] There are generally four types of parameters that reflect the ionizing radiation shielding performance of the target hybrid material: linear attenuation coefficient (LAC), half-value layer parameter (HVL), one-tenth value layer parameter (TVL), and radiation protection efficiency (RPE). After the MC prediction is completed, the target hybrid material with the relatively optimal ionizing radiation shielding performance can be selected from target hybrid materials with different mass ratios of candidate high-entropy compounds based on the prediction results. In the actual execution of MC prediction, the predicted parameters can be any one or more of the above four parameters. The specific selection can be adjusted according to actual needs, and this application does not impose specific limitations.

[0040] Step 0212: Based on the preset shielding performance standards, and according to the linear attenuation coefficient, half-value layer parameters, tenth-value layer parameters and / or radiation protection efficiency, select candidate hybrid materials from the target hybrid materials.

[0041] Specifically, based on the above implementation method, among the four parameters—linear attenuation coefficient (LAC), half-value layer parameter (HVL), tenth-value layer parameter (TVL), and radiation protection efficiency (RPE)—LAC and RPE are positively correlated with the ionizing radiation shielding performance of the target hybrid material, while HVL and TVL are negatively correlated. Furthermore, the linear attenuation coefficient (LAC), half-value layer parameter (HVL), and tenth-value layer parameter (TVL) can be converted using formulas. Therefore, when selecting materials with relatively optimal ionizing radiation shielding performance, the maximum LAC or RPE value, or the minimum HVL or TVL value, can be used as the preset shielding performance standard to select the target hybrid material with relatively optimal ionizing radiation shielding performance. For example, the target mixture includes five candidate high-entropy compounds with a mass percentage of 35%, 40%, 45%, 50%, and 55%. The linear decay coefficient (LAC) of each target mixture is calculated by MC prediction. It is found that the target mixture with a mass percentage of 55% of the candidate high-entropy compounds has the highest LAC parameter value. Therefore, the target mixture with a mass percentage of 55% of the candidate high-entropy compounds is selected as the candidate mixture and used as the reference standard for subsequent material preparation.

[0042] Please continue reading. Figure 1 The method for preparing ionizing radiation shielding material in the embodiments of this application further includes: Step 03: Prepare ionizing radiation shielding material based on the alternative mixed materials.

[0043] Specifically, after initial screening for synthetic compatibility using the SQS model based on DFT, and secondary screening for ionizing radiation shielding performance based on MC prediction, candidate hybrid materials that can be referenced during preparation can be obtained, and then the preparation process of ionizing radiation shielding materials can begin.

[0044] Please see Figure 6 Step 03 involves the following preparation process: Step 031a: Based on the candidate mixed material, the corresponding candidate metal source and complexing agent are uniformly mixed, and a precursor in the form of gel or film corresponding to the candidate mixed material is prepared within a preset temperature range.

[0045] Step 031b: Based on the candidate mixed materials, the corresponding candidate metal source and complexing agent are uniformly mixed, and a powdered precursor corresponding to the candidate mixed materials is prepared by co-precipitation or spray drying.

[0046] First, it should be noted that steps 031a and 031b are parallel embodiments. The specific choice of step 031a or step 031b depends on the specific requirements for the properties of the required precursor in the actual situation of the material preparation. If the required precursor needs to be in the form of a gel or film, then step 031a is selected; if the required precursor needs to be in the form of powder, then step 031b is selected.

[0047] Specifically, in steps 031a and 031b, for the preparation of the precursor, it is first necessary to select a corresponding metal source based on the alternative mixed materials. Among the required and alternative metal elements mentioned above, for tungsten, considering that the degree of hydrolysis may affect the formation of high-entropy compounds, ammonium salts containing tungsten anions, such as ammonium metatungstate, are generally used as the metal source corresponding to tungsten. For other elements, since the degree of hydrolysis of the corresponding salts generally does not affect the formation of high-entropy compounds, nitrates, acetates, and hydrochlorides of the corresponding metal elements can be used as the metal source. Among them, nitrates have strong oxidizing properties and are suitable for synthesis processes requiring high reactivity. Acetates have a milder hydrolysis reaction and are suitable for synthesis processes requiring lower reactivity. The main purpose of using acetates is to regulate the reaction rate in the formation of complex polymetallic oxides. In practical applications, for elements other than tungsten, salts with the same anion can be selected as the metal source according to the actual synthesis requirements. For example, for high-entropy oxides (Bi... 0.2 W 0.2 Gd 0.2 La 0.2 Sm 0.2 In the synthesis process of O2, the metal source used for tungsten is ammonium metatungstate, while the metal source for other metal elements is the corresponding nitrate.

[0048] Furthermore, for the selection of the complexing agent, organic compounds such as citric acid or ethylene glycol can be chosen. Given the metal source and complexing agent, for step 031a, the metal source and complexing agent are uniformly mixed using a sol-gel method and heated within a temperature range of 100℃ to 220℃ to prepare a gel-like dry gel precursor or a film-like dry film precursor. For step 031b, a uniformly mixed powder precursor is obtained using co-precipitation or spray drying methods.

[0049] Step 032: Heat the conductive mold based on pulse or DC current, and heat the precursor resistor placed in the conductive mold at a preset heating rate and peak temperature, and perform heat preservation within a first preset time range.

[0050] Specifically, once the precursor is prepared, it is typically placed in a conductive mold within an electric furnace for melting. The melting process generally employs ultrafast Joule heating sintering technology, utilizing the material's own resistance to achieve rapid heating, reaching the sintering temperature and densification within seconds to minutes. Specifically, this is achieved by applying a current pulse or direct current to the conductive mold, thereby utilizing the precursor's own resistance to heat up and achieve melting. The control parameters during energization are as follows: the precursor's heating rate is controlled at 100~300℃ / s, and the peak temperature of the precursor is controlled between 600~1400℃. After the precursor reaches its peak temperature, the electric furnace is switched to a heat preservation function to maintain the temperature of the conductive mold and the precursor within it. The heat preservation duration is generally 5~20 seconds. In this way, a single-phase high-entropy oxide ceramic with a density greater than or equal to 98% can be produced in a relatively short time, thus creating an ionizing radiation shielding material. In this way, by utilizing ultrafast Joule heating sintering technology, the energy consumption and time of the actual preparation process are greatly reduced. Combined with the SQS model primary screening and MC prediction secondary screening in the above embodiments, the energy consumption and time of the entire process from material selection to preparation completion are significantly reduced.

[0051] Please see Figure 7 The method for preparing ionizing radiation shielding material in the embodiments of this application further includes: Step 041: The ionizing radiation shielding material and the matrix resin are mixed and melted under molten or solution conditions, and then prepared by hot pressing or extrusion-pressing to form a target sample of a predetermined thickness.

[0052] Specifically, based on the above implementation method, since MC prediction is a simulation prediction, there may be certain errors between it and the actual situation, leading to a discrepancy between the ionizing radiation shielding performance of the prepared ionizing radiation shielding material and the predicted value. Moreover, since MC prediction is generally just a linear summation simulation, a higher mass proportion of the candidate mixed material in the MC prediction usually results in better predicted shielding performance. However, in actual experiments, it has been found that an increase in the mass proportion of the candidate mixed material is often accompanied by phenomena such as filler agglomeration, which negatively impacts the shielding performance and mechanical properties, leading to a significant difference between the predicted and actually measured shielding performance. Therefore, for example, after preparing the ionizing radiation shielding material, it is necessary to use actual experimental data to verify the ionizing radiation shielding performance of the material, so as to facilitate subsequent parameter adjustments and optimize the shielding performance of the ionizing radiation shielding material.

[0053] Before verifying the ionizing radiation shielding performance, a target sample with a similar structure to the ionizing radiation shielding device used in actual applications needs to be prepared based on the prepared ionizing radiation shielding material. For example, before verifying the ionizing radiation shielding performance, the prepared ionizing radiation shielding material is mixed and melted with a matrix resin under molten or solution conditions, and then hot-pressed or extruded-pressed to form a composite shielding film (corresponding to the target sample) with a thickness of 1-5 mm. Considering the dispersibility, mechanical properties, and antioxidant properties of the composite shielding film, compatibilizers and / or toughening agents and antioxidants can be added when mixing the ionizing radiation shielding material with the matrix resin. The types of compatibilizers, toughening agents, and antioxidants can be adjusted according to actual conditions, and this application does not impose specific limitations.

[0054] In addition, for example, besides adding a coupling agent, a mixture of ionizing radiation shielding material and matrix resin can be formed with fabric or metal mesh to form a sandwich structure, thereby improving the mechanical properties and durability of the composite shielding film.

[0055] Step 042: Measure the ionizing radiation shielding performance of the target sample within the preset energy range, and compare and verify the ionizing radiation shielding performance of the target sample with that of the candidate mixed material, so as to adjust the candidate mixed material according to the verification results.

[0056] Specifically, based on the above embodiments, for the target sample that has been prepared, the ionizing radiation shielding performance of the target sample can be measured using the standard measurement method for ionizing radiation shielding devices. The measurement results are then compared with the ionizing radiation shielding performance of the candidate mixed materials predicted by MC in the previous step. Based on the comparison results, the parameters of the candidate mixed materials can be fine-tuned to optimize the shielding performance of the prepared ionizing radiation shielding material.

[0057] In this way, the above-mentioned verification process can form a closed loop with the screening-prediction-preparation process in the preceding steps. While making great use of the screening-prediction-preparation process to save a lot of energy and time, the verification and fine-tuning process can be integrated into this process. This can avoid testing the prepared shielding material separately, and directly use the results of the actual shielding performance test and the MC prediction results to achieve rapid fine-tuning and optimization of the raw material parameters corresponding to the ionizing radiation shielding material.

[0058] Please see Figure 8 Furthermore, step 042 specifically includes: Step 0421: Within the preset energy range, perform a γ-ray transmittance test on the target sample to obtain the linear attenuation coefficient of the target sample.

[0059] Specifically, based on the above implementation method, using the linear attenuation coefficient (LAC) as the descriptive parameter for ionizing radiation shielding performance, after the target sample is prepared, a standard gamma-ray source can generally be used to perform gamma-ray transmittance testing on the target sample. The energy provided by the standard gamma-ray source needs to be the same as the energy used in the MC simulation process in the preceding step. For example, if the MC prediction process in the preceding step uses an energy range of 662 keV, then the standard gamma-ray source used should be... 137 Cs is used to generate gamma rays with an energy of 662 keV. Under these conditions, a gamma ray transmittance test can be performed to obtain the linear attenuation coefficient (LAC) of the target sample in the 662 keV energy region. This allows for subsequent comparison of the LAC of the target sample in the 662 keV energy region with the LAC of the candidate mixed material corresponding to the target sample in the 662 keV energy region when the MC prediction is performed, thereby verifying the ionizing radiation shielding performance.

[0060] Step 0422: Compare and verify the linear decay coefficient of the target sample and adjust the alternative mixed materials so that the linear decay coefficient of the target sample in the 662keV energy region is 20% higher than that of the preset sample with bismuth oxide or tungsten oxide as filler in the 662keV energy region.

[0061] Specifically, based on the above implementation method, if the deviation between the LAC and MC predicted by the target sample in the 662keV energy region and the LAC of the corresponding candidate mixed material in the 662keV energy region is less than or equal to the expected boundary value, then no adjustment is needed to the candidate mixed material, and the current ionizing radiation shielding material already meets the requirements. However, if the deviation between the two is greater than the expected boundary value, then it is necessary to adjust the mass ratio of the candidate high-entropy compound in the candidate mixed material, the heating rate, peak temperature, and holding time when melting the precursor, or the thickness when making the target sample, etc. After re-making the ionizing radiation shielding material, the shielding performance test is carried out again, and the verification process in the above implementation method is executed again until the deviation is less than or equal to the expected boundary value.

[0062] According to the experimental results, when the deviation between the two is less than or equal to the expected boundary value, the LAC of the target sample corresponding to the prepared ionizing radiation shielding material in the 662keV energy region is on average 20% higher than that of the LAC of the same specification with bismuth oxide or tungsten oxide as a single filler in the current related technology, which can show excellent ionizing radiation shielding performance.

[0063] In addition, please see Figures 9-11The target sample constructed from the ionizing radiation shielding material prepared according to the method in the embodiments of this application, and a sample of the same specifications constructed with lead oxide as the single filler, were subjected to a standard gamma-ray source. 137 A comparative experiment on ionizing radiation shielding performance was conducted under Cs (energy range of 662 keV), and the experimental results are as follows: Figures 9-11 As shown, where Figure 9 This is a blank control group. Figure 10 The target sample group in the above embodiments. Figure 11 For a sample group of the same specifications corresponding to lead oxide, the lower the instrument reading, the lower the measured radiation intensity, which means that the corresponding material has better ionizing radiation shielding performance. Therefore, according to... Figures 9-11 It can be seen that the ionizing radiation shielding performance exhibited by the ionizing radiation shielding material in the above embodiments is slightly better than the shielding performance of shielding materials constructed with lead oxide as a single filler in the current related technologies.

[0064] In addition to assessing ionizing radiation shielding performance, the mechanical properties, oxidation resistance, and thermal insulation of the target sample also need to be tested and verified according to the requirements of the ionizing radiation shielding material in different application scenarios, thereby adjusting the candidate hybrid material. The specific performance parameters to be tested and verified can be selected based on the actual situation, and this application does not impose specific limitations.

[0065] Please see Figure 12 The method for preparing ionizing radiation shielding material in the embodiments of this application further includes: 051: The antioxidant properties of the target sample were tested using the oxidation induction time method; and 052: Perform tensile property tests on the target specimen according to the preset standard.

[0066] Specifically, after the ionizing radiation shielding material is prepared, in addition to verifying the shielding performance, for example, it is also necessary to test the antioxidant properties and mechanical properties of the target sample to ensure that the ionizing radiation shielding device made of the ionizing radiation shielding material can meet the basic application requirements.

[0067] In some examples, the oxidation induction time (OIT) method is generally used to assess the antioxidant properties of the target sample. The specific procedure is as follows: 5–10 mg of the target sample is weighed and placed in an aluminum crucible. A hole is made in the center of the bottom of the crucible using a needle; in some cases, a perforated crucible may also be used. Liquid nitrogen is used as a protective agent. The initial temperature is set to 20 °C. The temperature is then increased to 190 °C at a rate of 20 °C / min under nitrogen purging (50 mL / min) and maintained for 5 min. Then, oxygen purging (50 mL / min) is switched, and the oxidation induction time (OIT value) is recorded.

[0068] The candidate high-entropy oxide used in the equipment selection of mixed materials is (Bi) 0.2 W 0.2 Gd 0.2 La 0.2 Sm 0.2 According to the experimental results, the oxidation induction time (OIT value) of the target sample was 130.65 min, which is about 4.81 times that of the sample of the same specification with bismuth oxide or tungsten oxide as the single filler. This is mainly because the enhanced lattice distortion in the shielding material obtained by high-temperature sintering enhances the interfacial interaction with the polymer matrix, thereby inhibiting oxidation. In addition, the synergistic effect between multiple components can further improve the antioxidant performance by regulating the electronic structure.

[0069] In some examples, the mechanical properties of the target specimens were tested using a universal electronic testing machine according to the national standard GB / T 1040-92 to assess tensile properties. The stress-strain curves showed that all composite materials underwent a transition from elastic to plastic deformation, with a stress plateau appearing in the plastic stage, exhibiting strain hardening characteristics. This reflects the microstructural reorganization (such as molecular chain orientation and filler network reconstruction) that occurs within the material with increasing strain, resulting in a secondary strength increase before fracture. Specifically, the measured elongation at break of the target specimen was 9.54%, which is four times that of a specimen of the same specification using bismuth oxide as the sole filler, and 2.8 times that of a specimen of the same specification using tungsten oxide as the sole filler.

[0070] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any way. Although this application has disclosed the preferred embodiment as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the technical solution of this application, based on the technical essence of this application and within the spirit and principles of this application, shall still fall within the protection scope of the technical solution of this application.

Claims

1. A method for preparing an ionizing radiation shielding material, characterized in that, The method includes: The mixing enthalpy of multiple high-entropy compounds was calculated based on density functional theory in order to screen out candidate high-entropy compounds that meet the preset mixing enthalpy criterion. The ionizing radiation shielding performance of the candidate high-entropy compounds is predicted based on Monte Carlo radiative transfer simulations to screen out candidate hybrid materials that meet the preset shielding performance standards. The ionizing radiation shielding material is prepared based on the alternative mixed materials.

2. The method according to claim 1, characterized in that, The metal elements in the candidate high-entropy compounds include a number of pre-selected mandatory metal elements and two of a number of candidate metal elements. The mandatory metal elements include bismuth, tungsten, and gadolinium, and the candidate metal elements include lanthanum, samarium, cerium, yttrium, and zirconium. The metal elements included in the candidate high-entropy compounds have the same molar ratio.

3. The method according to claim 1, characterized in that, The calculation of the enthalpy of mixture of multiple high-entropy compounds based on density functional theory, in order to screen candidate high-entropy compounds that meet the preset enthalpy of mixture criteria, includes: Construct a special quasi-stochastic structure model based on density functional theory; Based on the aforementioned special quasi-random structure model, the enthalpy of mixing of multiple high-entropy compounds is calculated; The high-entropy compounds with a mixing enthalpy between -15 kJ / mol and +5 kJ / mol were identified as the candidate high-entropy compounds.

4. The method according to claim 1, characterized in that, The step of predicting the ionizing radiation shielding performance of the candidate high-entropy compounds based on Monte Carlo radiative transfer simulations to screen candidate hybrid materials that meet preset shielding performance standards includes: The ionizing radiation shielding performance of the target hybrid material is predicted based on the Monte Carlo radiative transfer simulation to screen out the candidate hybrid materials. The target hybrid material includes the candidate high-entropy compound and a matrix material, wherein the matrix material is polypropylene, epoxy resin, polyurethane or rubber, and the mass ratio of the high-entropy compound in the target hybrid material is between 20% and 70%.

5. The method according to claim 4, characterized in that, The step of predicting the ionizing radiation shielding performance of the target hybrid material based on the Monte Carlo radiative transfer simulation to screen the candidate hybrid materials includes: Based on Monte Carlo radiative transfer simulation, the linear attenuation coefficient, half-value layer parameter, tenth-value layer parameter, and / or radiation protection efficiency of the target hybrid material are predicted within a preset energy range. Based on the preset shielding performance standard, and according to the linear attenuation coefficient, the half-value layer parameter, the tenth-value layer parameter, and / or the radiation protection efficiency, the candidate mixed materials are selected from the target mixed materials.

6. The method according to claim 5, characterized in that, The process of preparing the ionizing radiation shielding material based on the alternative mixed materials includes: According to the candidate mixed material, the corresponding candidate metal source and complexing agent are uniformly mixed, and a precursor in the form of a gel or film corresponding to the candidate mixed material is prepared within a preset temperature range; or According to the candidate mixed material, the corresponding candidate metal source and complexing agent are uniformly mixed, and a powder precursor corresponding to the candidate mixed material is prepared by co-precipitation or spray drying. The conductive mold is heated by pulse or DC current, and the precursor resistor placed in the conductive mold is heated at a preset heating rate and peak temperature, and heat preservation is performed within a first preset time range. Cooling is performed on the heat-insulated precursor to produce the ionizing radiation shielding material.

7. The method according to claim 6, characterized in that, The alternative metal source includes nitrates, acetates, hydrochlorides, or ammonium salts; the complexing agent includes citric acid or ethylene glycol; the preset temperature range is 100~220℃; the heating rate range is 100~3000℃ / s; the peak temperature range is 600~1400℃; and the first preset duration range is 5~20s.

8. The method according to claim 7, characterized in that, The method further includes: The ionizing radiation shielding material is mixed and melted with a matrix resin under molten or solution conditions, and then prepared by hot pressing or extrusion-pressing to form a target sample of a predetermined thickness. The ionizing radiation shielding performance of the target sample is measured within a preset energy range, and the ionizing radiation shielding performance of the target sample is compared and verified with that of the alternative mixed material, so as to adjust the alternative mixed material according to the verification results.

9. The method according to claim 8, characterized in that, The step of measuring the ionizing radiation shielding performance of the sample within a preset energy range and comparing and verifying the ionizing radiation shielding performance of the sample with that of the candidate hybrid material, and adjusting the candidate hybrid material according to the verification results, includes: Within the preset energy range, a gamma-ray transmittance test is performed on the target sample to obtain the linear attenuation coefficient of the target sample; The comparative verification was performed based on the linear decay coefficient of the target sample, and the alternative mixed materials were adjusted so that the linear decay coefficient of the target sample in the 662keV energy region was 20% higher than that of the preset sample with bismuth oxide or tungsten oxide as filler in the 662keV energy region.

10. The method according to claim 8, characterized in that, The method further includes: The antioxidant properties of the target sample were tested using the oxidation induction time method. Tensile property tests are performed on the target specimen according to preset standards.

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