Nanomaterial based on high pressure shearing and method for preparing the same

Abstract

This invention provides a high-pressure shear-based nanomaterial and its preparation method, applicable to various powder raw materials, such as black phosphorus. The method involves applying extremely high axial pressure and rotational shear force across the cross-section in a high-pressure torsion device, causing the powder material to undergo severe fragmentation and refinement under high-pressure shear conditions, ultimately producing a material with finer grains. The method includes preliminary pretreatment of the raw powder and high-pressure torsion treatment under specific pressure, pressure increase rate, and rotation speed conditions. Experimental results show that the method of this invention can effectively refine grains and improve the microstructure and mechanical properties of the material. Compared with traditional preparation methods, the preparation method of this invention has advantages such as short preparation cycle, simple process, and low cost, making it suitable for large-scale production and applicable to the preparation of various nanomaterials. This method provides a new technical approach for the efficient preparation of nanomaterials and has broad application prospects.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nanomaterial preparation, in particular to a nanomaterial based on high-pressure shearing and a preparation method thereof. BACKGROUND

[0002] Nanomaterials generally refer to a class of materials with a grain size of 1-100 nm. Due to the extremely small grain size and the greatly increased number of grain boundaries, nanomaterials exhibit more excellent mechanical properties, including yield strength, hardness, toughness and fatigue resistance, and also show more superior performance in optical, electrical, thermal and chemical stability. These characteristics of nanomaterials make them have wide application prospects in electronic devices, energy storage, catalysis, medicine and other fields. With the development of science and technology, the preparation and application of nanomaterials have become a research hotspot.

[0003] In order to better prepare nanomaterials, people have improved the traditional material processing technology, such as severe plastic deformation in plastic forming technology, which can effectively refine the grain size of the material and thus prepare nanomaterials. This preparation method not only has simple process and low cost, but also is easy to realize large-scale production, which provides strong support for the wide application of nanomaterials. By combining severe plastic deformation with high-pressure science, researchers have developed high-pressure torsion technology (HPT). As one of the typical large plastic deformation methods, high-pressure torsion technology makes the material undergo severe plastic deformation by applying high pressure and torsion force, that is, a torque is applied on the cross section while the material is axially compressed, so as to change the frictional resistance into frictional power, realize a certain torsional deformation, and at the same time, through simple compression deformation, achieve grain refinement, uniform organization, fragmentation and redistribution of the second phase. For example, the original grain of the material is severely broken and refined to form a sub-micron fine-grained structure.

[0004] The microstructure and mechanical properties of high pressure torsion (HPT) final samples are mainly affected by high aspect ratio, torsion angular velocity, extrusion speed, hydrostatic pressure, friction coefficient and temperature, etc. The maximum shear strain value is closely related to the thickness and radius of the sample, the pressure received, the number of rotations and the rotation speed. Generally, the thickness and radius of the sample during preparation are determined, so the maximum shear strain value is determined by the pressure conditions, the number of rotations and the speed. Different parameters may cause significant changes in material refinement and final performance. Specifically, if inappropriate process conditions are used, such as applying too high a pressure or performing too many rotations, not only can it not effectively promote the nanocrystallization of the material, but it may also exacerbate the diffusion behavior of atoms and the migration rate of grain boundaries, which directly accelerates the grain growth process, contrary to the expected goal. On the contrary, if lower pressure and rotation are used, the lack of torsional deformation refinement may result in a grain refinement degree that does not reach the nanoscale, and the refinement effect is poor. Therefore, the optimization and control of process parameters are crucial when using high pressure torsion technology to prepare nanomaterials.

[0005] Currently, the main methods for preparing nano-black phosphorus include mechanical exfoliation, liquid-phase ultrasonic exfoliation, electrochemical exfoliation, solvothermal method, chemical vapor deposition and ball milling, etc. Although these methods have achieved certain results in the preparation of nanomaterials, they also have significant limitations. First, the reaction conditions of many methods are harsh, usually requiring inert gas protection or specific high temperature and high pressure environments, which makes the process complex and energy-consuming. Second, existing methods are often prone to introduce impurities, and the use of organic solvents in some cases can cause potential harm to the environment, which limits its application range and sustainability to some extent. In addition, most of these methods require the use of high-value raw materials and solvents, and involve various complex chemical reactions and physical processes, requiring precise control of reaction conditions and experimental equipment, resulting in long production cycle and low efficiency, making it difficult to be effectively applied in large-scale production.

[0006] Taking black phosphorus as an example, black phosphorus is a relatively abundant element in nature, and there are three main allotropes: white phosphorus, red phosphorus and black phosphorus. Among the three allotropes, black phosphorus is attracting attention due to its unique thermodynamic stability. Black phosphorus has a layered structure, each layer consists of two atomic layers and contains two different phosphorus-phosphorus bonds (P-P bonds), which gives it unique physical and chemical properties. However, the traditional preparation process of black phosphorus faces many challenges, such as difficult preparation, harsh preparation conditions, etc., which limit the wide application of black phosphorus. In recent years, scientists have successfully prepared nanoscale black phosphorus using mechanical exfoliation method, and found that it has extremely high electron mobility, which opens up a new way for the research and application of black phosphorus. Compared with traditional black phosphorus, nanoscale black phosphorus has a larger specific surface area, more active sites and higher electron mobility, which makes nanoscale black phosphorus have wide application prospects in electronic devices, energy storage and biomedical fields.

[0007] Although the application prospect of nanoscale black phosphorus is broad, its efficient preparation is still a key problem to be solved. The existing preparation methods of nanoscale black phosphorus, although some achievements have been made in academic research, most of the methods still have the following problems: high energy consumption, harsh reaction conditions, long cycle and low efficiency. For example, although the mechanical exfoliation method and the liquid phase ultrasonic exfoliation method can prepare high-quality nanoscale black phosphorus, the process is complex and the energy consumption is high, and these methods cannot be effectively applied in large-scale production. In addition, impurities are easily introduced in the operation of these methods, which affects the quality of the final material. Therefore, it is urgent to develop a new preparation technology to solve the defects of existing methods, improve the preparation efficiency, and reduce energy consumption and environmental impact to meet the needs of large-scale production.

[0008] In summary, the existing technology has many problems in the preparation process of nanomaterials, especially in the quality control of materials, the adjustability of process and the industrial application. Therefore, it is urgent to develop an efficient, environmentally friendly and good industrial application prospect of nanomaterials preparation method. The present invention is born in this background, which successfully solves many defects in the existing technology by using a new high-pressure shearing preparation technology, and provides a new solution for the efficient preparation of nanomaterials. SUMMARY

[0009] The technical problem to be solved by the present invention is to provide a preparation method of nanomaterials based on high-pressure shearing, to solve the problems of uneven grain refinement, low efficiency, complex processing process and high energy consumption in the conventional methods of the prior art.

[0010] In order to overcome the defects of the prior art, the present invention provides a preparation method of nanomaterials based on high-pressure shearing conditions, comprising the following steps:

[0011] S1: The raw material powder with micron-level particle size is preliminarily pretreated to improve the uniformity and processability of the raw material;

[0012] S2: The pretreated raw material powder is pressed into a sample block through a mold;

[0013] S3: The formed sample block is filled into a gasket groove, and high-pressure shear treatment is performed by applying axial pressure and constant torque in a high-pressure device, specifically including:

[0014] a: Apply shear force at a set rotation speed under axial pressure;

[0015] b: Control the shear duration and total rotation angle to refine the material grains and form a nano-scale grain structure;

[0016] Compared with the prior art, the preparation method of the nano material based on high-pressure shear has the following advantages:

[0017] Efficient grain refinement: Compared with traditional methods, the present application avoids the problem of insufficient grain refinement in traditional methods by combining axial pressure and rotational shear force. Reduce energy consumption and improve efficiency: The sample is subjected to shear deformation and high-pressure shear by high-pressure torsion (HPT), which not only improves the efficiency of material refinement, but also reduces the dependence on high-temperature environment and reduces energy consumption.

[0018] Simplify the operation process: Through unified high-pressure torsion, the sample processing process is simplified, compared with the complex chemical reaction steps in traditional methods, the process of the present application is more direct and easy to control.

[0019] Suitable for large-scale production: Compared with existing methods for preparing nano materials, the process of the present application is simple, fast and low in cost, and is particularly suitable for industrial production.

[0020] In one possible implementation, in the step S1, the raw material powder is red phosphorus powder.

[0021] Compared with the prior art, the black phosphorus has unique advantages as a raw material, especially in the fields of electronics and energy storage. The characteristics include: high electron mobility: black phosphorus has excellent electron conductivity, which enables the nanomaterial prepared using black phosphorus powder as a raw material to have superior performance in electronic devices and sensors; high specific surface area: black phosphorus has a large specific surface area, which helps to improve the reactivity and electrochemical performance of the material, especially suitable for energy storage devices such as lithium batteries and supercapacitors; good chemical stability: black phosphorus is relatively stable under high temperature and humidity, suitable for various harsh application environments; therefore, using black phosphorus powder as a raw material can improve the performance of the final nanomaterial in the fields of electronics and energy storage.

[0022] In one possible implementation, in the step S1, the preliminary pretreatment includes: applying a pressure of 2-3 GPa to the raw material powder for 15 min or more, and heating the raw material powder to 700-800°C during the pressure holding period for 15 min.

[0023] Compared with the prior art, by applying a high pressure of 2-3 GPa, the structure of the raw material powder can be pretreated to promote the stability and uniformity of the crystal lattice. High pressure helps to improve the density of the powder and reduce the voids between particles, so that the subsequent high-pressure shearing process is more efficient; heating the raw material powder to 700-800°C during the pressure holding process can promote the heat treatment reaction of the powder and accelerate the rearrangement of the grains and the uniformity of the material. The temperature rise helps to improve the physical properties of the powder, including plasticity, toughness, etc., thereby improving the material processability and stability during subsequent pressing and high-pressure shearing processes; the above possible implementation pretreats the raw material powder by applying high pressure and heating, which makes the grains uniform and stable, thereby laying a foundation for the subsequent high-pressure shearing process, significantly improving the grain refinement effect of the nanomaterial and improving the production efficiency and material performance. Compared with the prior art, this scheme improves the efficiency of the preparation process by simple preliminary pretreatment, reduces energy consumption and time consumption, and is more suitable for industrial production.

[0024] In one possible implementation, in the step S1, the preliminary pretreatment is performed by a six-sided top press.

[0025] Compared with the prior art, the six-sided top press applies uniform multi-directional pressure to the raw material, achieving efficient pressing and uniform distribution. Compared with the traditional unidirectional pressing method, the six-sided top press can apply pressure in multiple directions at the same time, ensuring the uniformity and density of the powder. This device can better eliminate the voids between particles and promote the uniformity and densification of the grains.

[0026] In a possible implementation, in the step S3, the axial pressure is mechanical oil pressure, and the mechanical oil pressure is 40-60 MPa, and the rotation speed is 720° / hour.

[0027] Compared with the prior art, by adopting the technical scheme, the axial pressure of 40-60 MPa is applied, so that the sample can be fully stressed during high-pressure shearing, and the uniform refinement of the material grains is promoted. The moderate axial pressure helps the material to be subjected to severe plastic deformation, so that the effective refinement of the grains is realized. If the applied pressure is too low, the grain refinement may not be effectively promoted. If the applied pressure is too high, the material may be subjected to excessive diffusion, which is not conducive to the refinement. The rotation shear force is one of the key operating parameters in the application. By setting the rotation speed to 720° / hour, a high shear strain can be realized, so that the grain refinement of the material is effectively promoted. The increase of the rotation speed can increase the stress frequency of the material, so that the shear force can be more fully applied in each unit time, and the grain breakage and homogenization are promoted. If the rotation speed is too low, the shear strain may be insufficient, and the grain refinement may not be effectively realized. If the rotation speed is too high, the material may be subjected to excessive plastic deformation, which affects the stability of the material.

[0028] In a possible implementation, in the step S3, the shearing duration is 0.5 hours, and the total rotation angle is 360°.

[0029] Compared with the prior art, by adopting the technical scheme, the rotation angle of 360° is controlled during high-pressure shearing, so that the stress of the sample is uniformly distributed in the whole shearing region when the sample is subjected to the axial pressure. Under the action of the rotation shear force, the grains of the material are subjected to continuous and uniform deformation, which helps to realize more meticulous grain refinement. In each unit time, the increase of the rotation angle means the increase of the stress frequency of the sample, so that the shear stress can act on the material for a longer time, thereby accelerating the grain refinement process. In the above implementation of the application, the total rotation angle, the duration and the above axial pressure have a synergistic effect. The rotation of 360° in combination with appropriate pressure and rotation speed can improve the grain refinement effect through the synergistic effect. However, excessive rotation (greater than 360°) can cause the material to be subjected to excessive shear strain, so that the grains are broken too small. This can cause the grain size to be too small, which can damage the structural stability of the material, and even cause the grains to agglomerate or have irregular shapes, thereby affecting the mechanical properties of the material. A smaller rotation angle can cause the material to be subjected to insufficient shear strain, which cannot effectively promote the grain refinement. The grain refinement effect may not be as expected, so that the microstructure of the material remains unchanged or the refinement degree is not enough. This means that the material obtained finally may not achieve a nano-grain structure, which reduces the performance of the material and the problem of uneven grain refinement.

[0030] In a possible implementation, after the step S3, the method further comprises a step S4 of verifying, which comprises: S4: performing microstructure characterization on the sample after the high-pressure shearing in the step S3, to verify the grain refinement effect.

[0031] Compared with the prior art, by setting the shearing duration to 0.5 hours, the grain can be sufficiently subjected to the shearing force to achieve effective grain refinement while avoiding the problem of excessive grain refinement or non-uniformity caused by excessively long shearing time; and setting the rotation angle to 360° means that the rotation force is uniformly applied during the entire shearing process, which is crucial for grain refinement of the material, and the setting of the rotation angle ensures that the material is subjected to consistent shearing stress during the entire process, which is helpful for uniform grain refinement and effectively avoids non-uniform grain caused by local stress concentration.

[0032] In a possible implementation, in the step S3, the step S4 specifically comprises: analyzing the grain size of the sample by X-ray diffraction test, combining the Scherrer formula to calculate the degree of grain refinement; and photographing the sample by a scanning electron microscope and statistically analyzing the grain size of the sample by Nano measurer software to further verify the grain refinement effect.

[0033] Compared with the prior art, by XRD and the Scherrer formula, combined with SEM and Nanomeasurer analysis, the present application can achieve high-precision evaluation of the degree of grain refinement, ensure that the nanomaterial reaches the ideal grain size and distribution during preparation, and through accurate grain refinement detection, the process parameters can be adjusted in time during preparation to ensure that the quality of the final product is stable and consistent, and the grain refinement effect of the material is closely related to the performance (such as strength, conductivity, etc.), and accurate control and verification are helpful to improve the performance of the final product.

[0034] Another technical problem to be solved by the present application is to provide a method for preparing the nanomaterial by the above method, to solve the problems of non-uniform grain, unstable performance, and many impurities in the conventional nanomaterials in the prior art.

[0035] To overcome the defects of the prior art, the present application provides a nanomaterial prepared by the above method under high-pressure shearing conditions.

[0036] Compared with the prior art, the nanomaterial has the following advantages: the nanomaterial solves the problems of uneven grain refinement, high energy consumption and long production cycle in the prior art nanomaterial preparation method by introducing high-pressure shearing technology, and through accurate control of shearing conditions, uniform grain refinement and high performance of the material are ensured, and the production efficiency is improved and the energy consumption is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 X-ray diffraction patterns of the nanometer black phosphorus prepared in Example 1 of the present application and the black phosphorus only pretreated;

[0038] Figure 2 X-ray diffraction patterns of the black phosphorus prepared in the comparative example of the present application and the nanometer black phosphorus in Example 1;

[0039] Figure 3 Cross-section scanning electron microscope images and grain size statistical diagrams of the raw material black phosphorus after pretreatment of the present application;

[0040] Figure 4 Cross-section scanning electron microscope images and grain size statistical diagrams of the nanometer black phosphorus prepared in Example 1 of the present application;

[0041] Figure 5 Cross-section scanning electron microscope images and grain size statistical diagrams of the nanometer black phosphorus prepared in the comparative example of the present application;

[0042] Figure 6 Structure and sample stress schematic diagram of the non-equilibrium high-temperature and high-pressure device R-PE100 used in the present application;

[0043] Figure 7 Explosion schematic diagram of the non-equilibrium high-temperature and high-pressure device R-PE100 used in the present application;

[0044] Figure 8 3mm anvil assembly schematic diagram of the present application;

[0045] Figure 9 Sample ansys software stress analysis schematic diagram of the present application;

[0046] BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 8 In the figure, 1, anvil surface; 2, 3mm gasket; 3, sample. DETAILED DESCRIPTION

[0048] Firstly, those skilled in the art should understand that these embodiments are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can adjust them as needed in order to adapt to specific application occasions.

[0049] In the description of the embodiments of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances, and the MPa provided in the following implementation part and technical solution part of the present application is the machine oil pressure, and the corresponding anvil used is 3mm.

[0050] The present application provides a preparation method of nanomaterials based on high-pressure shearing, comprising the following steps:

[0051] S1: The raw material powder with micron-level particle size is preliminarily pretreated to improve the uniformity and processability of the raw material;

[0052] S2: The pretreated raw material powder is pressed into a sample block through a mold;

[0053] S3: The formed sample block is filled into a gasket groove, and high-pressure shearing treatment is carried out in a high-pressure device by applying axial pressure and constant torque, specifically including:

[0054] a: Shearing force is applied at a set rotating speed under axial pressure;

[0055] b: The shearing duration and total rotation angle are controlled to refine the material grains and form a nanoscale grain structure;

[0056] As a preferred scheme, in the step S1, the raw material powder is red phosphorus powder.

[0057] As a preferred scheme, in the step S1, the preliminary pretreatment includes: applying a pressure of 2-3GPa to the raw material powder and maintaining the pressure for 30min or more, and heating the raw material powder to 700-800℃ during the pressure maintaining period and maintaining the temperature for 15min.

[0058] As a preferred scheme, in the step S1, the device used for the preliminary pretreatment is a six-surface press.

[0059] As a preferred scheme, in the step S3, the axial oil pressure is 40-60MPa, and the rotating speed is 720° / hour.

[0060] As a preferred scheme, in the step S3, the shearing duration is 0.5 hours, and the total rotation angle is 360°.

[0061] As a preferred scheme, after the step S3, the method further comprises a step S4 of verification, which comprises: S4: performing microstructure characterization on the sample after the high-pressure shearing treatment in the step S3, and verifying the grain refinement effect.

[0062] As a preferred scheme, in the step S3, the step S4 specifically comprises: analyzing the grain size of the sample by X-ray diffraction testing, and combining the Scherrer formula to calculate the grain refinement degree; and further verifying the grain refinement effect by taking a picture of the sample through a scanning electron microscope and statistically analyzing the grain size of the sample by using a Nano measurer software.

[0063] The application further provides a nanomaterial prepared by the method under high-pressure shearing conditions.

[0064] The method for preparing the nanomaterial based on high-pressure shearing can effectively solve the problems of uneven grain refinement, low efficiency, high energy consumption and the like in the prior art, and further improves the quality and production efficiency of the nanomaterial, thereby providing strong support for the wide application of the nanomaterial. The method for preparing the nanomaterial based on high-pressure shearing can efficiently prepare nanomaterials including nanometer black phosphorus, and has a shorter preparation period, a simpler experimental process, higher efficiency and lower cost compared with the prior art such as the traditional mechanical exfoliation method, the liquid-phase ultrasonic exfoliation method, the electrochemical exfoliation method, the solvothermal method, the chemical vapor deposition method and the ball milling method. In addition, the experimental conditions are more relaxed, and are more suitable for large-scale industrial production. The application provides a novel method for preparing a nanomaterial based on high-pressure shearing, and provides suitable experimental conditions and a process flow, so that the grain refinement effect is optimal. The high-pressure torsion method has simple process, short experimental time and high preparation efficiency. The application can be produced by using a non-equilibrium high-temperature and high-pressure device (R-PE100), and is expected to realize future industrial production and promote large-scale production of nanomaterials. The experimental conditions for preparing the nanomaterial are greatly optimized, and the method has high reliability, success rate and good test repeatability, and is more suitable for industrial production requirements.

[0065] The following specifically describes the technical solutions of the application by combining the above technical solutions with specific embodiments:

[0066] Embodiment 1

[0067] The embodiment provides a nanomaterial based on high-pressure shearing and a preparation method thereof. The specific steps of the preparation method are as follows:

[0068] S1: raw material powder pretreatment

[0069] The micron-level red phosphorus powder is subjected to preliminary pretreatment by using a cubic press to obtain black phosphorus powder. The specific steps are as follows: a pressure of 3.0 GPa is applied to the raw material powder, and the pressure is maintained for 30 minutes, during which the raw material powder is heated to 750 DEG C and maintained for 15 minutes to improve the uniformity and processability of the powder.

[0070] S2: sample block forming

[0071] The pretreated black phosphorus powder is subjected to pressure powder forming by a mold to form a sample block.

[0072] S3: high-pressure shear treatment

[0073] The formed sample block is filled into the groove of a 3mm gasket, and the gasket is placed in the corresponding groove of the anvil. Then, high-pressure shear treatment is carried out in a high-pressure device (R-PE100), which specifically includes:

[0074] a. an axial oil pressure of 50 MPa is applied, and a shear force is applied at a set rotation speed of 720 DEG / h;

[0075] b. the shear duration is controlled to be 0.5 hours, and the total rotation angle is 360 DEG, so that the material grains are refined to form a nano-level grain structure.

[0076] S4: verification of grain refinement effect

[0077] The sample after high-pressure shear treatment is subjected to microstructure characterization. Specifically, it includes:

[0078] a. the sample grain size is analyzed by X-ray diffraction (XRD) test, and the grain refinement degree is calculated by combining the Scherrer formula;

[0079] b. the sample is photographed by a scanning electron microscope (SEM), and the sample grain size is statistically analyzed by combining the Nano measurer software to further verify the grain refinement effect.

[0080] Example 2:

[0081] The embodiment provides a nano material based on high-pressure shear and a preparation method thereof. The specific steps of the preparation method are as follows:

[0082] S1: raw material powder pretreatment

[0083] The micron-level red phosphorus powder is subjected to preliminary pretreatment by using a cubic press to obtain black phosphorus powder. The specific steps are as follows: a pressure of 2.5 GPa is applied to the raw material powder, and the pressure is maintained for 30 minutes, during which the raw material powder is heated to 750 DEG C and maintained for 15 minutes to improve the uniformity and processability of the powder.

[0084] S2: Sample block forming

[0085] The pretreated black phosphorus powder was formed into a sample block by press powder molding through a mold.

[0086] S3: High-pressure shear treatment

[0087] The formed sample block was filled into the groove of a 3mm gasket, and the gasket was placed in the corresponding groove of the anvil. Then, high-pressure shear treatment was performed in a high-pressure device (R-PE100), specifically including:

[0088] a. An axial oil pressure of 40MPa was applied, and a shear force was applied at a set rotation speed of 720° / hour;

[0089] b. The shear duration was controlled for 0.5 hours, and the total rotation angle was 360°, so that the material grains were refined to form a nano-scale grain structure.

[0090] S4: Verify the grain refinement effect

[0091] The sample after high-pressure shear treatment was subjected to microstructure characterization. Specifically including:

[0092] a. The sample grain size was analyzed by X-ray diffraction (XRD) test, and the grain refinement degree was calculated by combining the Scherrer formula;

[0093] b. The sample was photographed by scanning electron microscope (SEM), and the sample grain size was statistically analyzed by combining Nano measurer software to further verify the grain refinement effect.

[0094] The following also provides a comparative example:

[0095] Comparative Example:

[0096] The main difference between the comparative example and Example 1 is that the total rotation angle is 720°, and the treatment time is also different.

[0097] S1: Raw material powder pretreatment

[0098] The black phosphorus powder was pretreated using a cubic press, and the specific steps were as follows:

[0099] S1: For red phosphorus powder with micron-level particle size, a pressure of 2.5GPa was applied and maintained for 30 minutes, during which the raw material powder was heated to 750℃ and the temperature was maintained for 15 minutes to improve the uniformity and processability of the powder.

[0100] S2: Sample block forming

[0101] The pretreated black phosphorus powder is formed into a sample block by press powder molding through a mold.

[0102] S3: high-pressure shearing treatment

[0103] The formed sample block is filled into a groove of a 3mm pad, and the pad is placed in the corresponding groove of the anvil. Then, high-pressure shearing treatment is performed in a high-pressure device (R-PE100), specifically including:

[0104] a. 50MPa axial oil pressure is applied, and shearing force is applied at a rotation speed of 720° / hour;

[0105] b. The shearing duration is 1 hour, and the total rotation angle is 720°, so that the material grains are refined to form a nano-scale grain structure.

[0106] S4: verification of grain refinement effect

[0107] Microstructure characterization is performed on the sample after high-pressure shearing treatment. Specifically including:

[0108] a. The sample grain size is analyzed by X-ray diffraction (XRD) test, and the grain refinement degree is calculated by combining the Scherrer formula;

[0109] b. The sample is photographed by scanning electron microscope (SEM), and the sample grain size is statistically analyzed by combining Nano measurer software to further verify the grain refinement effect.

[0110] Table 1: raw material of the application and strong peak statistics table of examples 1-2:

[0111]

[0112] As shown in Table 1, Table 1 is a strong peak statistics table of the pretreated raw material (black phosphorus powder) of the application and the nano-material prepared in examples 1 and comparative examples, and Table 1 also summarizes Figures 1-2 the half-peak width values of each strong peak in

[0113] As shown in Table 1, the X-ray diffraction patterns of the black phosphorus prepared in example 1 and comparative example of the application and the raw material black phosphorus after only step S1 pretreatment; Figures 1-2 are Figure 1 the cross-sectional scanning electron microscope comparison chart of the black phosphorus prepared in example 1 of the application and the raw material black phosphorus;

[0114] Figures 3-4 are the cross-sectional scanning electron microscope chart and grain size statistical chart of the pretreated raw material black phosphorus of the application and example 1 of the application, respectively;

[0115] Figure 1The X-ray diffraction (XRD) comparison diagram of the pretreated black phosphorus raw material and the nano black phosphorus is shown. The diagram shows that the strength of the black phosphorus after high-pressure shearing treatment is greatly improved compared with the original black phosphorus, which further proves that the method of the application can effectively refine the crystal grains of the raw material, improve the crystallinity of the material, and improve the ordered structure;

[0116] Figures 3-4 The cross-section scanning electron microscope comparison diagram of the prepared black phosphorus in Example 1 of the application and the raw material black phosphorus is shown. The raw material black phosphorus usually shows larger particles and uneven distribution in the cross-section SEM diagram, showing the characteristics of coarse and large particles. After high-pressure shearing treatment, the crystal grains of the black phosphorus are significantly refined, the particles are more uniform, the crystal grain distribution is more dense, and the sub-micron crystal grain structure is shown. This shows that the high-pressure shearing technology of the application effectively breaks the original crystal grains of the black phosphorus and promotes the uniform refinement of the crystal grains.

[0117] Figure 4 The cross-section scanning electron microscope diagram and the grain size statistical diagram of the nano black phosphorus prepared in Example 1 of the application are shown. In Example 1, Figure 4 The grain size of the material is measured and counted to verify the effect of high-pressure shearing treatment on grain refinement. The details of the sample are photographed by scanning electron microscopy (SEM), and the grain size is accurately analyzed and counted by using Nano measurer software. The diagram shows that the grain size of the material after high-pressure shearing treatment is significantly reduced and shows a uniform refinement trend, meeting the requirements of nano material preparation.

[0118] As Figure 2 shown, Figures 4-5 Figure 2 The X-ray diffraction diagram of the black phosphorus prepared in the comparative example of the application and the nano black phosphorus in Example 1 is shown. Table 1 is Figures 1-2 a statistical table of the half-peak width values of the strong peaks in Figures 4-5 The cross-section scanning electron microscope diagram of the black phosphorus in the comparative example of the application Figure 5 ) and the comparative diagram of the SEM grain size statistics of Example 1 nano black phosphorus are shown.

[0119] Figure 2 The X-ray diffraction diagrams of Example 1 and the comparative example are shown. As can be seen from Figure 2 , the half-peak width of the comparative example is narrowed due to excessive rotation, which shows that excessive rotation leads to excessive alignment and structure optimization of the crystal grains. Compared with the wide peak in Example 1, the grain refinement effect in Example 1 is more uniform and meets the requirements of nano materials. Therefore, excessive rotation may cause unnecessary changes in the structure of the material and affect the final performance.

[0120] Figures 4-5 ​The black phosphorus section scanning electron microscope contrast diagram of the embodiment and the comparative example is shown, the section structure contrast of the nano black phosphorus prepared in example 1 and the raw material black phosphorus in the comparative example is shown, from the figure, it can be seen that the nano black phosphorus prepared in example 1 has a clear grain structure, and the sample in the comparative example shows larger particles or grains, which further proves that the sample in example 1 is subjected to high-pressure shearing treatment, the degree of grain crushing is higher, the particle size is smaller, so that the performance of the material is improved, the hardness and other mechanical properties are enhanced, and in the comparative example, due to the difference in treatment time and rotation angle, the grain refinement effect of the material does not reach the best, so that the grain is larger, thereby affecting the performance of the final nano material, which further proves that the rotation angle, pressure energy parameters are further controlled and selected, and the synergistic effect is achieved.

[0121] And Figure 4 In example 1, the average particle size of the raw material is 0.01917 μm, and the grain size distribution is relatively concentrated, which indicates that the grain of the sample is relatively small and has little fluctuation. Figure 5 In the comparative example, under the treatment condition of 720 degrees, the grain size after treatment is obviously larger. Most of the grain sizes are concentrated in a larger size range (0.05 μm to 0.15 μm), and the average size of the grain is 0.106 μm. Compared with example 1, the average value of the grain size after treatment has increased significantly, and the grain is more uneven, which indicates that the grain is subjected to greater stretching and shearing force in the high-pressure shearing process, which further proves the rationality of setting the rotation angle of 360 degrees in the present application.

[0122] Figures 6-9 As shown, the specific equipment and stress condition in example 1 of the present application are shown, Figure 6 The structural schematic diagram and stress analysis schematic diagram of the high-pressure shearing device R-PE100 are shown, the layout of each component in the equipment is clear, which is used to realize the effective preparation of the nano material in the method of the present application; Figure 7 It is an explosion schematic diagram of R-PE100, from which the structure of each part of the device can be clearly seen, and the working principle and experimental conditions under high-pressure environment are further understood; Figure 8 It is an assembly schematic diagram of the 3mm anvil of the present application, which shows the assembly mode of the 3mm anvil, so that each sample in the experimental process can be uniformly treated, Figure 8 It includes: 1, anvil surface; 2, 3mm gasket; 3, sample; Figure 9 It is an ansys software stress analysis schematic diagram of the sample of the present application, through the stress analysis of ANSYS software, the deformation process of the sample under different pressure conditions is shown in detail, which helps to understand how these mechanical actions affect the grain structure of the material, so as to realize higher level of grain refinement.

[0123] In the description of the embodiments of the present application, it should be noted that the terms of direction or position relationship such as "inner", "outer" and the like indicated in the description of the present application are based on the direction or position relationship shown in the drawings, which is merely for the convenience of description, and does not indicate or imply that the device or member must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0124] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "in this embodiment", "specific example" or "some examples" and the like means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in the specification and the features of the different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0125] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for producing nanomaterials based on high pressure shearing, characterized by, The method comprises the following steps: S1: preliminary pretreatment of raw material powder with micron-level particle size to improve the uniformity and machinability of the raw material; S2: compression molding of the pretreated raw material powder through a mold to form a sample block; S3: filling the molded sample block into a gasket groove and performing high-pressure shearing treatment in a high-pressure device by applying axial pressure and constant torque, specifically including: a: applying shearing force at a set rotation speed under axial pressure; b: controlling the shearing duration and total rotation angle to refine the material grains and form a nano-level grain structure; In the step S1, the raw material powder is red phosphorus powder; The preliminary pretreatment includes: applying a pressure of 2-3 GPa to the raw material powder and maintaining the pressure for 30 min or more, and heating the raw material powder to 700-800℃ during the pressure maintaining period and maintaining the temperature for 15 min; In the step S3, the axial pressure is mechanical oil pressure, and the mechanical oil pressure is 40-60 MPa, and the rotation speed is 720° / hour; In the step S3, the shearing duration is 0.5 hour, and the total rotation angle is 360°.

2. The method for preparing nanomaterials based on high pressure shearing according to claim 1, wherein, In the step S1, the equipment used for the preliminary pretreatment is a six-surface press.

3. The method of claim 1, wherein the high pressure shear is in the range of 1 to 10 GPa. After the step S3, a step S4 verification is further included, which comprises:

4. The method for producing a nanomaterial based on high-pressure shearing according to claim 3, wherein The step S4 specifically comprises: through X-ray diffraction test, analyzing the sample grain size, combining Scherrer formula The degree of grain refinement is calculated; the sample is photographed by a scanning electron microscope, and statistical analysis of the sample grain size is performed by combining Nano measurer software to further verify the grain refinement effect.

5. A nanomaterial, characterized in that, S4: microstructure characterization of the sample after the high-pressure shearing treatment of the step S3 to verify the grain refinement effect. The nano-material is prepared by the method of any one of claims 1-4 under high-pressure shearing conditions.

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