Transmission electron microscope sample preparation device and method for high-entropy alloy nanoparticles

Abstract

The invention provides a transmission electron microscope sample preparation device and method for high-entropy alloy nanoparticles, and relates to the field of high-entropy alloys and microscopic characterization thereof. The preparation device comprises a substrate and a round cover with holes, grooves of the substrate are in one-to-one correspondence with the holes in the round cover, and the device is made of a metal material with high temperature resistance. According to the preparation method provided by the invention, transmission electron microscope characterization results of the nanoscale high-entropy alloy particles and the high-quality high-entropy alloy nanoparticles can be obtained. The obtained high-entropy alloy particles are uniform in distribution, controllable in size and high in experiment success rate, and a plurality of samples can be prepared at the same time. Through the pulse laser deposition technology, the high-entropy alloy nano-particles which are evenly distributed and controllable in size can be obtained, the experiment success rate can be increased, pollution in the experiment process can be avoided, the capacity of preparing a plurality of transmission electron microscope samples at the same time is achieved, and a high-quality microscopic characterization result can be obtained; and the quality and the preparation efficiency of the high-entropy alloy transmission electron microscope nanoparticle sample are remarkably improved.

Description

Technical Field

[0001] The invention relates to the field of high entropy alloys and microscopic characterization thereof, and in particular to a device and method for preparing a high entropy alloy nanoparticle transmission electron microscope sample. Background Art

[0002] Transmission Electron Microscope (TEM) is a high-resolution microscopic technique that uses an electron beam to pass through a sample to generate an image. TEM can provide atomic-level spatial resolution and observe in detail the microscopic features of the material's internal structure, defects, and interfaces. High-entropy alloys (HEAs) are new alloys composed of five or more elements in equal proportions. Through the regulation of multiple metal components, HEAs show phase behavior and physical and chemical properties that are completely different from traditional alloys, with unique structures and properties such as high strength, high hardness, excellent corrosion resistance and thermal stability.

[0003] The preparation methods of high entropy alloy nanoparticles mainly include mechanical alloying, chemical reduction, spray pyrolysis, thermal decomposition, etc. These methods have their own characteristics, but they all have certain shortcomings. Mechanical grinding is difficult to control the size and composition uniformity of particles, and high-energy ball milling may lead to irregular particle morphology and the introduction of impurities. Although the chemical reduction method can generate relatively uniform particles, the reaction conditions are difficult to accurately control, the required high entropy alloy salt solution is highly toxic, and it is easy to leave residual precursors or by-products. The spray pyrolysis method also requires a high entropy alloy salt solution, and there are challenges in controlling particle size and morphology, which affects the subsequent TEM sample preparation. The thermal decomposition method is prone to particle agglomeration and growth under high temperature conditions, and it is difficult to obtain small-sized uniform particles. Therefore, in order to obtain high-quality high-entropy alloy nanoparticle observation samples, it is necessary to improve the existing technology. Summary of the invention

[0004] Purpose of the invention: To solve the above problems, the present invention provides a transmission electron microscope sample preparation device for high entropy alloy nanoparticles, which can provide multiple sample preparation capabilities.

[0005] The present invention also provides a method for preparing a transmission electron microscope sample preparation device using the above-mentioned high entropy alloy nanoparticles, aiming to obtain nanoscale high entropy alloy particles and obtain high-quality high entropy alloy nanoparticle transmission electron microscope characterization results.

[0006] To achieve the above-mentioned purpose, the technical solution of the transmission electron microscope sample preparation device of high entropy alloy nanoparticles provided by the present invention is:

[0007] A transmission electron microscope sample preparation device for high entropy alloy nanoparticles comprises a substrate, a perforated round cover covering the upper surface of the substrate, and a TEM grid; the substrate is provided with a plurality of grooves, the perforated round cover is provided with a plurality of communicating holes corresponding to the grooves one by one, and a TEM grid is provided in each groove.

[0008] Further, the groove, the TEM grid placed in the groove and the corresponding hole are aligned.

[0009] Furthermore, the base and the round cover with holes are fixed by bolt connection.

[0010] Furthermore, the base, the round cover with holes and the bolts are all made of high temperature resistant metal materials.

[0011] Furthermore, the TEM grid is an ultra-thin carbon film or a graphene support film.

[0012] The high entropy alloy nanoparticle sample preparation method provided by the present invention using the transmission electron microscope sample preparation device of the high entropy alloy nanoparticles can adopt the following technical scheme, including the following steps:

[0013] S1. Clean the transmission electron microscope sample preparation device of high entropy alloy nanoparticles with alcohol ultrasonic cleaning, dry and place for a set time, put the TEM grid into the groove in turn, and cover it with a round cover with holes;

[0014] S2, the transmission electron microscope sample preparation device of the high entropy alloy nanoparticles described in S1 is adhered to the center position of the PLD base support by means of an adhesive and heated and cured, and at the same time, the high entropy alloy target is adhered to the center position of the PLD target support and heated and cured, and then the PLD base support and the PLD target support are placed in the PLD device;

[0015] S3, close the PLD door and evacuate the PLD device; then start heating until the specified temperature;

[0016] S4, after the temperature rises to the specified temperature, the target rotation is turned on, the laser is turned on, and the pre-sputtering step is performed;

[0017] S5, after the pre-sputtering is completed, set the laser parameters, turn on the laser for formal sputtering; after the formal sputtering is completed, turn off the heating, cool the PLD device to room temperature, and take out the high entropy alloy nanoparticle observation sample;

[0018] S6. Load the high entropy alloy nanoparticle observation sample prepared in S5 into a transmission electron microscope sample rod and place it in a transmission electron microscope for observation. Use high-resolution TEM and scanning transmission mode to observe the atomic image of the high entropy alloy nanoparticles.

[0019] Furthermore, the adhesive is silver glue or aluminum-based conductive tape.

[0020] Furthermore, the vacuum environment in the PLD device described in S3 is: firstly pumped to 1Pa by a mechanical pump, and then pumped to 3.0×10-5Pa by a molecular pump.

[0021] Furthermore, the pre-sputtering laser parameters are consistent with those of the formal sputtering, the target rotates at 4 rpm, the laser voltage is 18.3 kV, the actual energy is 200 mj, and the pre-sputtering time is not less than 10 minutes.

[0022] Furthermore, the transmission electron microscope sample holder in S6 is a single-tilt or multi-tilt sample holder, and the characterization mode can adopt high-resolution TEM and STEM.

[0023] Beneficial effects:

[0024] The present invention provides an efficient and stable high entropy alloy nanoparticle preparation device and method, which solves many problems existing in the prior art and has the following beneficial effects:

[0025] 1. Uniform distribution of particles and controllable size: By precisely controlling the preparation conditions and process parameters, uniformly distributed and size-controlled high-entropy alloy nanoparticles can be obtained. This is crucial for subsequent transmission electron microscopy (TEM) characterization, ensuring the accuracy and consistency of the observation results.

[0026] 2. High experimental success rate: The device of the present invention is reasonably designed, easy to operate, and can prepare multiple samples at the same time, which greatly improves the success rate and efficiency of the experiment. In particular, in the preparation process of high entropy alloy nanoparticles, it prevents the agglomeration and growth of particles, ensuring the high quality of the samples.

[0027] 3. Strong material adaptability: The device is made of high-temperature resistant metal materials, which can withstand temperatures up to 800°C and adapt to the high-temperature links in the preparation process. This feature not only ensures the durability of the device, but also ensures the stability of the sample under high temperature conditions.

[0028] 4. Avoid contamination: Through strict cleaning and operation procedures, including alcohol cleaning, ultrasonic treatment and vacuum drying, the risk of sample contamination is greatly reduced. In addition, the design of the device can effectively avoid contamination of samples during the preparation process and ensure the purity of the samples.

[0029] 5. Efficient sputtering: Pulsed laser deposition (PLD) technology is used for sample preparation. By precisely controlling the laser voltage, energy, frequency and other parameters, the sputtered high entropy alloy presents a single atom or cluster form, which is evenly distributed on the transmission electron microscope grid. The subsequent heating environment promotes the nucleation of atoms and clusters, which significantly improves the sputtering efficiency and sample quality. This method can not only obtain high-quality samples in a short time, but also reduce material waste.

[0030] 6. Multi-sample preparation capability: The device of the present invention is reasonably designed and can prepare multiple samples at the same time, which improves the experimental efficiency and repeatability of sample preparation. This is very beneficial for experiments that require a large number of samples for characterization and research.

[0031] 7. High-quality microscopic characterization: The high-entropy alloy nanoparticle samples prepared by the present invention have good characterization effects under a transmission electron microscope, and can observe in detail the microscopic characteristics of the material such as the internal structure, defects and interfaces, providing a reliable experimental basis for the research of high-entropy alloy materials.

[0032] In summary, the high entropy alloy nanoparticle sample preparation device and method provided by the present invention significantly improve the quality and preparation efficiency of the sample and overcome the shortcomings of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the assembly three-dimensional structure of the transmission electron microscope sample preparation device for high entropy alloy nanoparticles of the present invention.

[0034] Figure 2 The figure is a cross-sectional view of the assembly of the transmission electron microscope sample preparation device for high entropy alloy nanoparticles of the present invention.

[0035] Figure 3 Schematic diagram of pulsed laser sputtering experiment for preparing the device and method of the present invention.

[0036] Figure 4 STEM image (a) and HRTEM image (b) of the transmission electron microscopy sample of high entropy alloy nanoparticles.

[0037] Figure 5 Electron microscope images of small particles / clusters of high entropy alloy after adjusting the pulse laser parameters and temperature. DETAILED DESCRIPTION

[0038] like Figures 1 to 3 As shown, an embodiment of the present invention provides a transmission electron microscope sample preparation device for high entropy alloy nanoparticles, including a bolt 1, a perforated round cover 2, a substrate 3, and a TEM grid 4. The materials of the bolt 1, the round cover 2, and the substrate 3 are all high-temperature resistant alloys, and the diameters of the substrate 3 and the perforated round cover 2 are both 3mm. The thickness of the substrate 3 is 4mm, and there are 4 grooves evenly distributed on the surface of the substrate 3, and the depth of the grooves is 0.5mm. The perforated round cover 2 is 0.5mm thick, and 4 perforations are distributed at the positions corresponding to the grooves of the substrate 3, with a diameter of 2.5mm. The diameter of the TEM grid 4 is 3mm. The high entropy alloy target 6 used in conjunction with the preparation device has a diameter of 15mm and a thickness of 3mm.

[0039] Based on the above-mentioned transmission electron microscope sample preparation device of high entropy alloy nanoparticles, the present invention also provides a high entropy alloy nanoparticle sample preparation method, comprising the following steps:

[0040] S1. Clean the transmission electron microscope sample preparation device with alcohol ultrasonic cleaning, dry and place for 24 hours, put the TEM grid 4 to be characterized into the corresponding groove of the substrate 3 in turn, cover it with a round cover with holes 2 and tighten the bolt 1.

[0041] S2. Glue the TEM sample preparation device to the center of the PLD base holder through conductive glue or silver glue, and glue the high entropy alloy target 6 to the center of the PLD target holder. After the TEM sample preparation device is glued to the PLD base holder and the high entropy alloy target 6 is glued to the PLD target holder, both are heated on a 100°C heating table for 5 minutes to solidify the colloid, and then the PLD base holder and the PLD target holder are placed together in the PLD device.

[0042] S3. Close the PLD door, turn on the mechanical pump, evacuate to below 5Pa, turn off the mechanical pump and turn on the molecular pump, evacuate to 3.0×10-5Pa, start heating at this time, set the heating rate to 20℃ / min, and the target temperature to 500℃.

[0043] S4. After the temperature of step S3 rises to the specified temperature of 500°C, turn on the target rotation, set the parameters to 4rpm, close the baffle valve, set the laser voltage to 18.3kv, the actual energy to 200mj, the laser frequency to 2HZ, the number of times to 1200, and turn on laser 5 for the pre-sputtering step.

[0044] S5. After the pre-sputtering in S4 is finished, open the baffle valve, set the laser frequency to 1HZ, the number of times to 200, and turn on laser 5 to officially start sputtering. After the end, the temperature can be maintained at 500℃ for 30 minutes. The longer the insulation time, the larger the particle size. Then turn off the heating, cool the furnace to room temperature, and take out the sample.

[0045] S6. After the sample prepared in S5 is loaded into the transmission electron microscope sample holder, it can be placed in the transmission electron microscope for observation. The transmission electron microscope sample holder is a single-tilt or multi-tilt sample holder. The prepared transmission sample uses high-resolution TEM and scanning transmission (STEM) mode to observe the atomic image of high-entropy alloy nanoparticles. The final shooting result is as follows: Figure 4 shown.

[0046] The preparation process is finished.

[0047] If you need to make smaller high entropy alloy nanoparticles or clusters, adjust the temperature and sputtering laser parameters in S4, set the temperature to 20°C, the laser voltage to 18.3kv, the laser energy to 200mj, the laser frequency to 1HZ, the sputtering times to 20 times, and the operation of S5 remains unchanged. Smaller high entropy alloy nanoparticles or clusters can be made, and the electron microscope imaging results are as follows: Figure 5 shown.

Claims

1. A transmission electron microscope sample preparation device for high entropy alloy nanoparticles, characterized in that: The invention comprises a base (3), a round cover with holes (2) covering the upper surface of the base (3), and a TEM grid (4); the base (3) is provided with a plurality of grooves, the round cover with holes (2) is provided with a plurality of communicating holes corresponding to the grooves one by one, and each groove is provided with a TEM grid (4).

2. The transmission electron microscope sample preparation device for high entropy alloy nanoparticles according to claim 1, characterized in that: The groove, the TEM grid (4) placed in the groove and the corresponding hole are aligned.

3. The transmission electron microscope sample preparation device for high entropy alloy nanoparticles according to claim 1, characterized in that: The base (3) and the round cover with holes (2) are connected and fixed by bolts (1).

4. The transmission electron microscope sample preparation device for high entropy alloy nanoparticles according to claim 3, characterized in that: The base, the round cover with holes and the bolts are all made of high temperature resistant metal materials.

5. The transmission electron microscope sample preparation device for high entropy alloy nanoparticles according to claim 1, characterized in that: TEM grids are ultra-thin carbon films or graphene support films.

6. A method for preparing a high entropy alloy nanoparticle sample using the transmission electron microscope sample preparation device for high entropy alloy nanoparticles according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, cleaning the transmission electron microscope sample preparation device of high entropy alloy nanoparticles with alcohol ultrasonic cleaning, drying and leaving for a set time, placing the TEM grid into the groove in turn, and covering it with a round cover with a hole (2); S2, the transmission electron microscope sample preparation device of the high entropy alloy nanoparticles described in S1 is adhered to the center position of the PLD base support by means of an adhesive and heated to cure, and at the same time, the high entropy alloy target material (6) is adhered to the center position of the PLD target support and heated to cure, and then the PLD base support and the PLD target support are placed in the PLD device; S3, close the PLD door and evacuate the PLD device; then start heating until the specified temperature; S4, after the temperature rises to the specified temperature, the target rotation is turned on, the laser is turned on (5), and a pre-sputtering step is performed; S5, after the pre-sputtering is completed, set the laser parameters, turn on the laser for formal sputtering; after the formal sputtering is completed, turn off the heating, cool the PLD device to room temperature, and take out the high entropy alloy nanoparticle observation sample; S6. Load the high entropy alloy nanoparticle observation sample prepared in S5 into a transmission electron microscope sample rod and place it in a transmission electron microscope for observation. Use high-resolution TEM and scanning transmission mode to observe the atomic image of the high entropy alloy nanoparticles.

7. The method for preparing a high entropy alloy nanoparticle sample according to claim 6, characterized in that: The adhesive is silver glue or aluminum-based conductive tape.

8. The method for preparing a high entropy alloy nanoparticle sample according to claim 7, characterized in that: The vacuum environment in the PLD device described in S3 is: firstly evacuated to 1Pa by a mechanical pump, and then evacuated to 3.0×10-5Pa by a molecular pump.

9. The method for preparing a high entropy alloy nanoparticle sample according to claim 8, characterized in that: The pre-sputtering laser parameters are consistent with those of the formal sputtering, with the target rotating at 4 rpm, the laser voltage at 18.3 kV, the actual energy at 200 mj, and the pre-sputtering time being no less than 10 minutes.

10. The method for preparing a high entropy alloy nanoparticle sample according to claim 9, characterized in that: The transmission electron microscope sample holder described in S6 is a single-tilt or multi-tilt sample holder, and the characterization mode can adopt high-resolution TEM and STEM.

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