CN111272547A - Pressure head for transmission electron microscope in-situ pressure test and manufacturing method thereof - Google Patents

Pressure head for transmission electron microscope in-situ pressure test and manufacturing method thereof Download PDF

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Publication number
CN111272547A
CN111272547A CN202010077750.4A CN202010077750A CN111272547A CN 111272547 A CN111272547 A CN 111272547A CN 202010077750 A CN202010077750 A CN 202010077750A CN 111272547 A CN111272547 A CN 111272547A
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sample
diamond
substrate
transmission electron
pit
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CN111272547B (en
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聂安民
张奕志
王宏涛
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Zhejiang University ZJU
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Zhejiang University ZJU
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K10/00—Welding or cutting by means of a plasma
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/02—Details
    • G01N3/04—Chucks
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/02—Details
    • G01N3/06—Special adaptations of indicating or recording means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
    • G01N2001/2866—Grinding or homogeneising
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0058—Kind of property studied
    • G01N2203/006—Crack, flaws, fracture or rupture
    • G01N2203/0067—Fracture or rupture
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0058—Kind of property studied
    • G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
    • G01N2203/0075—Strain-stress relations or elastic constants
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/04—Chucks, fixtures, jaws, holders or anvils
    • G01N2203/0464—Chucks, fixtures, jaws, holders or anvils with provisions for testing more than one specimen at the time
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/06—Indicating or recording means; Sensing means
    • G01N2203/0641—Indicating or recording means; Sensing means using optical, X-ray, ultraviolet, infrared or similar detectors

Abstract

The method for manufacturing the pressure head for the transmission electron microscope in-situ pressure test comprises the steps of obtaining a base rod, selecting a diamond particle, fixing the diamond particle at the end part of the base rod, exposing a diamond area of the pressure head to be processed, and cutting a cylinder with the diameter of 5-20 mu m in the exposed area of the diamond by using FIB; the cylinder was made perpendicular to the FIB ion beam, and the pressure plane of the cylinder was machined. The pressure head comprises a rod-shaped substrate and a diamond particle fixed at the end of the substrate, wherein a cylindrical protrusion with the diameter of 5-20 mu m is arranged in an exposed area of the diamond particle exposed out of the substrate, and the end face of the cylindrical protrusion is formed by FIB processing. The invention has the advantages of simple manufacturing process, short processing period and processing cost saving.

Description

Pressure head for transmission electron microscope in-situ pressure test and manufacturing method thereof
Technical Field
The invention relates to an in-situ experiment system capable of being loaded on a transmission electron microscope sample rod when pressure in-situ experiment is carried out in a transmission electron microscope.
Background
Transmission Electron Microscope (TEM) is a Transmission electron microscope that projects an accelerated and focused electron beam onto a very thin sample, where the electrons collide with atoms in the sample and change direction, thereby producing solid angle scattering. The magnitude of the scattering angle is related to the density and thickness of the sample, and therefore, different bright and dark images can be formed, and the images can be displayed on an imaging device (such as a fluorescent screen, a film and a photosensitive coupling component) after being amplified and focused.
The resolution of the transmission electron microscope is much higher than that of the optical microscope, and can reach 0.1-0.2 nm, and the magnification is tens of thousands to millions of times. Thus, the use of a transmission electron microscope can be used to observe fine structures of a sample, even structures of only one column of atoms, several tens of thousands of times smaller than the smallest structures that can be observed with an optical microscope. TEM is an important analytical method in many scientific fields related to physics and biology, such as cancer research, virology, materials science, and nanotechnology, semiconductor research, etc.
The in-situ experiment of the transmission electron microscope means that a specific action (such as pressure or tension) is applied to a material or a tissue to be researched inside the transmission electron microscope to cause the material or the tissue to be researched to generate physical change, so that the change mechanism of a substance can be conveniently researched. The transmission electron microscope in-situ compression experiment is an important in-situ experiment method in material science, and a sample is compressed by a pressure head to observe the deformation and fracture process of the sample.
When the in-situ pressure experiment is carried out, the sample and the pressure head are loaded on the sample rod, and the sample, the clamp for clamping the sample and the pressure head are regarded as a set of experiment system loaded on the sample rod.
For the indenter: in conducting the pressure test, the pressure head surface is in contact with the sample and transmits the pressure to the sample. The requirement is that 1, the hardness of the pressure head is not lower than that of the sample, so that the influence of the deformation of the pressure head on a pressure experiment is avoided, and the stress of the sample is interfered; 2. the surface roughness of the pressure head reaches the nanometer level and above, and the uneven stress of the sample caused by factors such as the surface of the pressure head is not smooth enough is avoided. When the sample is uniformly stressed, it can be considered that the sample is subjected to a single stress when the secondary experiment is conducted. If the sample is stressed unevenly, the sample is stressed by multiple stresses, the stress condition is complex, and the atom migration condition under single stress is difficult to characterize.
Therefore, the pressure head material for the transmission electron microscope in-situ pressure experiment is mainly diamond, and the surface roughness of the pressure head is required to reach the nano level and above.
At present, the diamond indenter for the in-situ experiment of the transmission electron microscope mainly uses an instrumented indentation experiment part 2 which conforms to ISO 14577-2 Metal Material hardness and Material parameters: the indenter used in the inspection and calibration of the test machine, such as that used in the ultrasonic elastic deformation of nanoscaled, published in Science, by AmitBanerjee et al. The indenter is specially designed for hardness test and measurement, and the cost is high. However, in the in-situ pressure experiment, only a regular diamond pressure head with nano-scale roughness is needed to be obtained, and the hardness test performance is not necessary in the in-situ pressure experiment, so that unnecessary cost waste is caused by using the pressure head.
In addition, the existing manufacturing method of the diamond indenter is as follows: the method comprises the steps of obtaining a copper column as a matrix of a pressure head, adhering diamonds to the end of the matrix, grinding the matrix step by using a diamond grinding wheel, cleaning the matrix after grinding each time, and obtaining the diamond pressure head after grinding and cleaning for multiple times, wherein a mechanical sharpening method (CN 2017108011351) of a high-precision diamond Vickers pressure head is published by Harbin industry university, and the diamond pressure head with a nano scale is obtained by using a grinding method for multiple times. The manufacturing method for enabling the diamond pressure head to meet the precision requirement through grinding by the grinding wheel inevitably requires that the surface roughness of the grinding wheel per se reaches the nanometer level and above. The grinding device is difficult to manufacture and the grinding process is complex.
For the clamp and the sample, the existing sample for the transmission electron microscope in-situ pressure experiment is generally in a rod shape, a sample sleeve for loading the sample is arranged on a nanometer driver of a sample rod, and the rod-shaped sample is tightly pressed on the sleeve through a radial screw. At present, when a pressure experiment is carried out, a targeted sample is usually a diamond nano micro column, and the diamond nano micro column is usually processed on diamond particles to be in a nano level. Then the diamond particles are bonded on the substrate which is fixed on the sleeve of the sample rod. After the in-situ pressure experiment is completed, if the crystallography characterization of the diamond nano-micro column is needed, cutting off diamond particles of the diamond nano-micro column, and then loading another sample rod for the crystallography characterization experiment for the experiment. This is because the sample rod for the transmission electron microscope is classified into a plurality of types of sample rods according to the experimental functions, for example, an in-situ experimental sample rod providing an in-situ experimental function, an observation sample rod capable of conveniently observing images of samples at various crystallographic angles, and the like. In-situ test sample rods can generally only observe samples from a limited angle, and the observation capability is generally weak. The sample rod for observation has no in-situ experiment function. Therefore, in practical experiments, the sample after in situ experiment needs to be transferred to another transmission electron microscope sample rod for detailed characterization. However, at present, the sample for performing the in-situ pressure test cannot be directly loaded on the sample rod for observation, and the nano-micro column needs to be cut and separated from the diamond particles to be loaded on the sample rod for observation for more characterization experiments.
D. Kiener et al, In Nature materials, published In situ nano-compression of an irradial copper, disclose a method for transferring a sample after a transmission electron microscope In-situ experiment to another transmission electron microscope sample rod, which comprises the steps of performing the In-situ experiment by using the In-situ experiment sample rod, cutting out a critical area (nano-microcolumn) of the sample by using a focused ion beam, purging by using argon ions, adhering to a transmission electron microscope copper mesh, and carrying on the transmission electron microscope sample rod for characterization. The method is complex to operate, and new defects are easily introduced in the focused ion beam cutting process, so that the persuasion of the sample characterization result is influenced.
The sample itself is also a key factor in the success of the in situ pressure experiment. Therefore, how to prepare a sample meeting the requirements is also important. The ultra elastic deformation of nanoscaled diamond particles, published by Amit Banerjee et al in Science, revealed the high elasticity exhibited by diamond particles at the nanoscale. In order to further research the diamond nano-micro column, a large amount of diamond nano-micro column samples need to be prepared. The above article also discloses a method for preparing diamond nanocolumns by depositing a diamond film on a Si substrate using chemical vapor deposition and preparing a nanodiamond needle by plasma induced etching. However, due to the adoption of the etching method to prepare the diamond microcolumns, the residual microcracks on the surface of the diamond microcolumns have potential influence on the mechanical properties of the nano-microcolumns.
Disclosure of Invention
The invention provides an in-situ pressure experiment system for a transmission electron microscope, which comprises a sample, a clamp and a pressure head, wherein the sample can be loaded on a sample rod, and can be conveniently disassembled from the sample rod and then transferred to another sample rod, and the surface precision of the pressure head reaches the nanometer level. In the in-situ pressure experiment, the sample is loaded on the nanometer driver of the sample rod, the pressure head is fixed on a fixing part (such as a circuit board) at the head end of the sample rod, and the driver of the sample rod drives the sample to move towards the direction close to the pressure head so as to provide positioning and pressure for the sample. Keeping the sample for a period of time after applying pressure to the sample, and then enabling the sample to leave the pressure head; alternatively, the sample is removed from the indenter immediately after the sample is applied.
The invention aims to provide a method for manufacturing a transmission electron microscope in-situ pressure test pressure head with high surface precision by using a simple process and the pressure head.
The method for manufacturing the pressure head for the transmission electron microscope in-situ pressure test comprises the following operations: obtaining a substrate, selecting a diamond particle, fixing the diamond particle at the end of the substrate, exposing a diamond area of a pressure head to be processed, and cutting a cylinder with the diameter of 5-20 mu m in the exposed area of the diamond by using FIB (focused ion beam); the cylinder was made perpendicular to the FIB ion beam, and the pressure plane of the cylinder was machined. The cylinder is used as a pressure head for providing pressure for the sample during the in-situ pressure test, and the pressure plane is used as a working surface which is in direct contact with the sample. The FIB uses strong current ion beams to strip surface atoms, and can finish micro-scale and nano-scale surface appearance processing. The pressure head of FIB processing is used, the nano-scale surface precision can be obtained only by one-time processing, the process is simple, and the processing precision is high.
In order to improve the processing efficiency of the pressure head, the following steps are further defined: firstly, a femtosecond laser is used for processing a boss with the diameter of 10-50 mu m on an exposed area of the diamond, and then a cylinder with the diameter of 5-20 mu m is processed by FIB. The femtosecond laser is high in processing speed, firstly, a boss is roughly processed by the femtosecond laser, then, the boss with the diameter of 10-50 mu m is finely processed into a cylinder with the diameter of 5-20 mu m by FIB, the workload of the FIB is reduced, and the processing time of one pressure head can be controlled within 45 min.
Preferably, the FIB and/or femtosecond laser processes the remaining region concentric with the substrate. The femtosecond laser and FIB, during processing, will determine the processing area and the remaining area through images (such as concentric circles), and the remaining area refers to the area where no material is removed. The remaining area is concentric with the substrate such that the working face of the indenter is concentric with the substrate.
Preferably, after the substrate is obtained, a pit is dug at the end of the substrate, the pit is aligned with the substrate, the diamond particle part is placed in the pit, and the diamond particles outside the pit are exposed. Preferably, the pits are ball and socket, cylindrical pits, conical pits, or pits matching the diamond particles.
Preferably, the fixing scheme of the diamond and the substrate is as follows: and (3) obtaining a base body with a pit at the end part, or processing the pit at the end part of the base body, injecting glue into the pit, then placing the diamond particles into the pit, and fixing and maintaining the position of the diamond particles until the glue is solidified.
Alternatively, the diamond particles may be fixed to the substrate by means of holding the gemstone by means of claw setting, band setting, or the like.
The pressure head for the transmission electron microscope in-situ pressure test comprises a rod-shaped substrate and a diamond particle fixed at the end of the substrate, wherein a cylindrical protrusion with the diameter of 5-20 mu m is arranged in an exposed area of the diamond particle exposed out of the substrate, and the end face of the cylindrical protrusion is formed by FIB processing. The diameter of 5~20 mu m sets up, is on the one hand in order to avoid the pressure head to shelter from the sample, and on the other hand, if the sample has a plurality of diamond microcolumns, the interval of adjacent diamond microcolumns is about 10 mu m to touch other diamond microcolumns during avoiding pressure test.
Preferably, the cylindrical projection is coaxial with the base. Preferably, the substrate has a pit for accommodating the diamond particles, and the diamond particles are partially embedded in the pit; the diamond particles are fixedly bonded with the substrate, or the diamond particles and the substrate are fixedly embedded by claws or by wrapping.
The process for manufacturing the diamond pressure head is simple, and the FIB is matched equipment for preparing a sample by a transmission electron microscope, so that the processing time and the processing cost are saved; the processing precision of FIB reaches nanometer level, so the surface precision of the manufactured diamond pressure head is guaranteed. The diamond indenter of the present invention may be mounted on a fixed part of the sample rod or a nano-actuator of the sample rod as long as it can provide pressure to the sample.
In a second aspect, the present invention is directed to a method and a fixture for loading a diamond microcolumn sample on a sample rod, and conveniently transferring the sample from one sample rod to another sample rod.
The sample loading method of the transmission electron microscope in-situ pressure test comprises the steps of obtaining a clamp, wherein the clamp comprises a base rod base body, the base rod base body is divided into a connecting part and a sample loading part, the connecting part is provided with the shape and the size of a sample sleeve capable of being inserted into a sample rod, and the sample loading part is provided with a loading plane; obtaining a semi-copper net for a transmission electron microscope, and adhering and fixing the nano micro-cylinder sample on a contact finger of the semi-copper net; and then placing the sample-free area of the semi-copper net into a clamping part, and fixing the semi-copper net. Such as by adhesive attachment, or by other means of fasteners.
The loaded sample faces outwards, the pressure head is opposite to the loaded sample, the sample rod is started, the nano driver enables the sample to be aligned to the pressure head and then close to the pressure head, and the in-situ pressure experiment is carried out. When the sample needs to be transferred to other sample rods, the clamp is removed from the sample rod, and the clamp and the sample are transferred to another sample rod together.
Preferably, the clamp comprises a screw, a screw hole is formed in the loading plane, the screw is matched with the screw hole, and the head of the screw and the loading plane form a clamping position for clamping a sample.
Preferably, the number of the nano-micro column samples is multiple, and each nano-micro column sample is fixed on one copper strip. Preferably, the semi-copper mesh is centered on the base rod.
A sample anchor clamps for TEM normal position pressure test, including the base rod, the base rod is connecting portion and dress appearance portion, and connecting portion have the telescopic shape and the size of sample that can insert the sample pole, and dress appearance portion has the loading plane that can fix copper mesh or half copper mesh.
Preferably, the clamp comprises a screw, a screw hole is formed in the loading plane, the screw is matched with the screw hole, and the head of the screw and the loading plane form a clamping position for clamping a sample.
Preferably, the connecting part is a complete cylinder, the sample loading part is an incomplete cylinder with a part of circle cut off, the diameter of the connecting part is equal to that of the sample loading part, the circumference of the connecting part and the loading plane of the sample loading part form a step, and the sample loading part is parallel to the axis of the base rod on the loading plane. Preferably, the dimensions of the screw head are greater than or equal to the radial width of the loading plane. Preferably, the bottom of the screw head is flat.
The size of the head of the screw is as large as possible, and the threaded part of the screw is as small as possible on the premise that the thread pair is firmly combined, so that the effective area of a clamping part between the screw and the loading plane is as large as possible, and the reliability of sample loading is ensured. The copper net and the sample can be conveniently mounted on the sample rod by using the screw for clamping, and the copper net can be conveniently taken down from the clamp, so that the sample is convenient to move.
Preferably, the base rod is a copper rod with the diameter of 1mm, the sample loading part is a semi-cylinder formed by cutting off a semi-cylinder from the copper rod, the central axis of the base rod passes through the loading plane, and the loading plane is provided with a threaded hole of M0.5.
By using the clamp and the sample loading method, the sample can be loaded on the sample rod quickly and reliably, and the clamp and the sample can be quickly detached from the current sample rod and transferred to another sample rod without influencing the sample.
In a third aspect of the present invention, it is an object to provide a method for preparing a diamond nanopillar sample with high surface quality for use in a transmission electron microscope.
A method for preparing a diamond nanocolumn sample with high surface quality, performing the following operations: putting the semi-copper net into FIB, cutting a block sample on the diamond particles to be measured by using the FIB, adhering the block sample on a contact finger of the semi-copper net, and cutting the block sample into a cylindrical diamond nano-micro column with the diameter of less than 200 nm; and (3) purging the sample by using plasma to remove the amorphous layer on the surface of the sample. Stick-and-cut are two basic functions of the FIB.
And finishing the sample preparation, and taking the diamond nano micro-column and the semi-copper net as the sample as a whole. After the in-situ test is carried out, the sample can be directly loaded into a sample rod for observation without cutting the diamond sample again.
Preferably, before the nano-micro column is prepared on the bulk sample, the bulk sample is trimmed into a semi-enclosed structure having two side arms and a connecting arm, the connecting arm is located between the two side arms, and the free ends of the side arms are used for preparing the nano-micro column.
Preferably, one nanopillar is disposed on each side arm of the semi-surrounding structure.
Preferably, the semi-enclosing structure is U-shaped.
The diamond nano-micro column sample prepared by the method has regular and controllable shape, surface fluctuation with the height of only a few atomic steps and high surface quality.
The invention has the advantages that:
1. the process for manufacturing the diamond pressure head is simple, and the FIB is matched equipment for preparing a sample by a transmission electron microscope, so that the processing time and the processing cost are saved.
2. The diamond is prepared into a blocky sample which can be loaded by all sample rods before the transmission electron microscope in-situ experiment is carried out, the blocky sample is adhered to the contact finger of the semi-copper mesh, the blocky sample and the semi-copper mesh form a complete sample together, the complete sample per se or the complete sample and the clamp are moved together between the sample rods, the sample is convenient to move, and the influence of re-cutting on the sample after the pressure experiment is eliminated.
3. Two nano-micro columns can be processed by one block sample, so that each block sample can be subjected to two pressure experiments. One block sample is loaded on the contact finger of one semi-copper net, more than one contact finger is arranged on the semi-copper net, and a plurality of block samples can be loaded on one semi-copper net, so that a plurality of pressure experiments can be carried out. The diamond nano-micro column sample prepared by using FIB has regular and controllable shape, surface fluctuation with the height of only a few atomic steps and high surface quality.
Drawings
Figure 1 is a schematic view of the indenter of the present invention.
Figure 2 is a low magnification photograph of a diamond indenter aligned with a sample under a transmission electron microscope.
Fig. 3 is a schematic view of the clamp of the present invention.
Figure 4 is a schematic view of the clamp of the present invention-a semi-copper mesh-sample and indenter loaded on a sample rod.
FIG. 5 is a schematic view of a sample block fixed on a finger.
Fig. 6 is a transmission electron micrograph of a diamond sample.
Figure 7 is a high resolution transmission electron micrograph of the edge of a diamond sample.
Detailed Description
The specific embodiments of the present invention will be further explained with reference to the accompanying drawings.
In-situ pressure experiment system for transmission electron microscope
As shown in fig. 4, the in-situ pressure experiment system for a transmission electron microscope includes a sample 35, a jig enabling the sample 35 to be loaded on a sample rod and to be easily detached from the sample rod and then transferred to another sample rod, and an indenter 34 having a surface roughness of the order of nanometers. In the in-situ pressure experiment, the sample 35 is loaded on the nano-driver 31 of the sample rod, the pressure head 34 is fixed on a fixing member (such as a circuit board) at the head end of the sample rod, and the driver of the sample rod drives the sample 35 to move towards the direction close to the pressure head 34 to provide pressure for the sample 35. Holding the sample 35 for a period of time after applying pressure to the sample 35 and allowing the sample 35 to move away from the indenter 34; alternatively, the sample 35 may be moved away from the indenter 34 immediately after the sample 35 has been pressurized.
In some embodiments, as shown in fig. 1, the indenter 34 includes a rod-shaped substrate 5 and one diamond 4 particle fixed to an end of the substrate 5, wherein an exposed region of the diamond 4 particle exposed to the substrate 5 has a cylindrical protrusion with a diameter of 5 to 20 μm, and an end surface of the cylindrical protrusion is formed by FIB processing. The diameter of 5-20 μm is set, on one hand, in order to avoid the pressure head 34 to shield the sample 35, and on the other hand, if the sample 35 has a plurality of diamond 4 micro-columns, the distance between adjacent diamond 4 micro-columns is about 10 μm, so as to avoid touching other diamond 4 micro-columns during the pressure test.
The cylindrical projection is coaxial with the base body 5. The substrate 5 is provided with pits 22 for containing diamond 4 particles, and the diamond 4 particles are partially embedded in the pits 22; the diamond 4 particles are fixed with the matrix 5 in a bonding way, or the diamond 4 particles are fixed with the matrix 5 by claw embedding or embedding.
Of course, the present experimental system may also employ existing indenters 34.
In some embodiments, as shown in fig. 3, the sample holder 32 comprises a base rod divided into a connecting portion 2 and a sample loading portion 14, the connecting portion 2 having a shape and size of a sample sleeve into which a sample rod can be inserted, and the sample loading portion 14 having a loading plane capable of fixing a copper mesh or semi-copper mesh 2.
As shown in fig. 3, the clamp includes a screw 16, a screw hole 15 is provided in the loading plane, the screw 16 matches with the screw hole 15, and the head of the screw 16 and the loading plane form a clamping position for clamping a sample 35. Or, the clamp includes a rivet, a rivet hole in interference fit with the rivet is arranged in the loading plane, and the head of the rivet and the loading plane form a clamping position for clamping the sample 35.
As shown in fig. 3, the connecting portion 2 is a complete cylinder, the sample loading portion 14 is an incomplete cylinder with a partial circle cut off, the connecting portion 2 and the sample loading portion 14 have the same diameter, the circumference of the connecting portion 2 and the loading plane of the sample loading portion 14 form a step, and the sample loading portion 14 is parallel to the axis of the base rod on the loading plane. The size of the head of the screw 16 is greater than or equal to the radial width of the loading plane. The bottom of the head of the screw 16 is flat.
The size of the head of the screw 16 is as large as possible, and the threaded part of the screw 16 is as small as possible on the premise that the thread pair is firmly combined, so that the effective area of a clamping part between the screw 16 and a loading plane is as large as possible, and the loading reliability of the sample 35 is ensured. The screw 16 is used for clamping, so that the copper mesh and the sample 35 can be conveniently arranged on the sample rod, and the copper mesh can be conveniently taken down from the clamp, so that the sample 35 can be conveniently moved.
In a specific embodiment, the base rod is a copper rod with a diameter of 1mm, the sample loading part 14 is a semi-cylinder formed by cutting a semi-cylinder from the copper rod, the central axis of the base rod passes through a loading plane, and a threaded hole of M0.5 is arranged on the loading plane.
Of course, the present invention may also adopt the scheme that the semi-copper mesh 2 is adhered to the base rod, and the base rod is inserted into the sleeve of the sample rod to realize the fixation of the sample 35.
As shown in fig. 5, the sample 35 for the transmission electron microscope in-situ pressure test is a bulk sample 35 with a thickness of no more than 200nm, and the bulk sample 35 has the nano-micro column 13 thereon.
In some embodiments, as shown in fig. 5, a bulk sample 35 having a semi-enclosed structure of two side arms 12 and a connecting arm 1, wherein the connecting arm 1 is located between the two side arms 12, and the free end of the side arm 12 is a nanocolumn 13. The size of the bulk sample 35 allows the sample 35 to be loaded onto any sample rod, facilitating the migration of the sample 35 from the in situ test sample rod to the observation sample rod.
Method for making indenter
A method of making an indenter 34 for transmission electron microscopy in situ pressure testing, comprising the operations of: obtaining a substrate 5, selecting a diamond 4 particle, fixing the diamond 4 particle on the end part of the substrate 5, exposing the diamond 4 area of a pressure head 34 to be processed, and cutting a cylinder with the diameter of 5-20 microns in the exposed area of the diamond 4 by using FIB (focused ion beam); the cylinder was made perpendicular to the FIB ion beam, and the pressure plane of the cylinder was machined. The cylinder serves as a pressure head 34 for applying pressure to a sample 35 during in situ pressure testing, and the pressure plane serves as a working surface for direct contact with the sample 35. The FIB uses strong current ion beams to strip surface atoms, and can finish micro-scale and nano-scale surface appearance processing. The pressure head 34 of FIB processing is used, the nano-scale surface precision can be obtained only by one-time processing, the process is simple, and the processing precision is high.
In order to improve the processing efficiency of the pressure head 34, the following steps are further defined: firstly, a femtosecond laser is used for processing a boss with the diameter of 10-50 mu m on an exposed area of the diamond 4, and then a cylinder with the diameter of 5-20 mu m is processed by FIB. The femtosecond laser is high in processing speed, firstly, a boss is roughly processed by the femtosecond laser, then, the boss with the diameter of 10-50 mu m is finely processed into a cylinder with the diameter of 5-20 mu m by FIB, the workload of the FIB is reduced, and the processing time of one pressure head 34 can be controlled within 45 min.
In FIB and/or femtosecond laser processing, the axis of the reserved area is parallel to the axis of the substrate 5. The femtosecond laser and FIB, during processing, will determine the processing area and the remaining area through images (such as concentric circles), and the remaining area refers to the area where no material is removed. The axis of the remaining area is parallel to the axis of the base body 5, so that the working surface of the ram 34 is perpendicular to the axis of the base body 5.
A pit 22 is provided at the end of the substrate 5, the diamond 4 particles are partially put in the pit 22, and the diamond 4 particles outside the pit 22 are exposed. Preferably, the pits 22 are ball and socket, cylindrical pits, conical pits, or pits that match the diamond 4 grains.
In some embodiments, the fixing scheme of the diamond 4 and the substrate 5 is: obtaining a substrate 5 with a pit 22 at the end, or processing the pit 22 at the end of the substrate 5, injecting glue into the pit 22, then placing the diamond 4 particles into the pit 22, and fixing and maintaining the positions of the diamond 4 particles until the glue is solidified.
In some embodiments, the diamond 4 and substrate 5 may be fixed by clamping, wrapping, or the like to fix the diamond 4 particles to the substrate 5.
Pressure head
As shown in fig. 1 and 2, the indenter 34 for the transmission electron microscope in-situ pressure test includes a rod-shaped substrate 5 and one diamond 4 particle fixed on an end of the substrate 5, wherein an exposed area of the diamond 4 particle exposed out of the substrate 5 has a cylindrical protrusion with a diameter of 5-20 μm, and an end surface of the cylindrical protrusion is formed by FIB processing. The diameter of 5-20 μm is set, on one hand, in order to avoid the pressure head 34 to shield the sample 35, and on the other hand, if the sample 35 has a plurality of diamond 4 micro-columns, the distance between adjacent diamond 4 micro-columns is about 10 μm, so as to avoid touching other diamond 4 micro-columns during the pressure test.
The cylindrical projection is coaxial with the base body 5. The substrate 5 is provided with pits 22 for containing diamond 4 particles, and the diamond 4 particles are partially embedded in the pits 22; the diamond 4 particles are fixed with the matrix 5 in a bonding way, or the diamond 4 particles are fixed with the matrix 5 by claw embedding or embedding.
Sample loading method
In the method for loading the sample 35 for the transmission electron microscope in-situ pressure test, a clamp is obtained, as shown in fig. 3 and 4, the clamp comprises a base rod, the base rod is divided into a connecting part 2 and a sample loading part 14, the connecting part 2 has the shape and the size of a sample 35 sleeve capable of being inserted into a sample rod, and the sample loading part 14 has a loading plane; obtaining a copper mesh for a transmission electron microscope, dividing the whole copper mesh into two half copper meshes 2, and adhering and fixing the nano micro-cylinder 13 sample 35 on copper bars of the half copper meshes 2; and then placing the area without the sample of the semi-copper net 2 into a clamping part, and fixing the semi-copper net 2. Such as by adhesive attachment, or by other means of fasteners.
As shown in fig. 4, with the loaded sample 35 facing outward, the indenter 34 opposite the loaded sample 35, the sample rod is actuated, and the nano-actuator 31 aligns the sample 35 with the indenter 34 and then approaches the indenter 34 for in situ pressure testing. When the sample 35 needs to be transferred to another sample rod, the clamp is removed from the sample rod, and the clamp and the sample 35 are transferred to another sample rod.
The clamp comprises a screw 16, a screw hole 15 is formed in the loading plane, the screw 16 is matched with the screw hole 15, and the head of the screw 16 and the loading plane form a clamping position for clamping a sample 35.
The number of the nano micro-pillars 13 is a plurality of samples 35, and each nano micro-pillar 13 sample 35 is fixed on a copper strip. The semi-copper mesh 2 is aligned with the base rod.
By using the clamp and the sample 35 loading method, the sample 35 can be loaded on the sample rod quickly and reliably, and the clamp and the sample 35 can be detached from the current sample rod and moved to another sample rod quickly without influencing the sample 35.
Clamp apparatus
As shown in fig. 3, the sample holder 32 for the tem compression test comprises a base rod, the base rod is divided into a connecting part 2 and a sample loading part 14, the connecting part 2 has a shape and a size of a sample sleeve capable of being inserted into a sample rod, and the sample loading part 14 has a loading plane capable of fixing a copper mesh or a semi-copper mesh 2.
In some embodiments, as shown in fig. 3, the clamp includes a screw 16, a screw hole 15 is formed in the loading plane, the screw 16 is matched with the screw hole 15, and the head of the screw 16 and the loading plane form a clamping position for clamping the sample 35.
The connecting part 2 is a complete cylinder, the sample loading part 14 is an incomplete cylinder with a part of circle cut off, the diameter of the connecting part 2 is equal to that of the sample loading part 14, the circumference of the connecting part 2 and the loading plane of the sample loading part 14 form a step, and the sample loading part 14 is parallel to the axis of the base rod on the loading plane. Preferably, the size of the head of the screw 16 is greater than or equal to the radial width of the loading plane. Preferably, the bottom of the head of the screw 16 is flat.
The size of the head of the screw 16 is as large as possible on the premise of being accommodated in the sample cavity of the transmission electron microscope, and the threaded part of the screw 16 is as small as possible on the premise of firm combination of the thread pair, so that the effective area of the clamping part between the screw 16 and the loading plane is as large as possible, and the loading reliability of the sample 35 is ensured. The screw 16 is used for clamping, so that the copper mesh and the sample 35 can be conveniently arranged on the sample rod, and the copper mesh can be conveniently taken down from the clamp, so that the sample 35 can be conveniently moved.
Preparation method of diamond nano micro-column sample
A method for preparing a diamond nanocolumn 13 with high surface quality, performing the following operations: putting the semi-copper net 2 into FIB, cutting a block sample 35 on the diamond 4 particles to be detected by using the FIB, and adhering the block sample 35 to the contact finger 21 of the semi-copper net 2; trimming the block diamond 4 into a nanometer microcolumn 13 with the diameter of less than 200 nm; the sample 35 is purged with plasma to remove the amorphous layer on the surface of the sample 35. As shown in fig. 5, the diamond nanocolumn is adhered to the contact finger of the semi-copper mesh.
The sample 35 is prepared, and the diamond nanocolumn 13 and the half copper mesh 2 are collectively regarded as the sample 35. After the in situ test is performed, the sample 35 can be loaded directly into the observation sample rod without having to re-cut the diamond 4 sample 35.
Before the nano-micro column 13 is prepared on the bulk sample 35, the bulk sample 35 is trimmed to a semi-enclosed structure having two side arms 12 and a connecting arm 1, the connecting arm 1 is located between the two side arms 12, and the free ends of the side arms 12 are used for preparing the nano-micro column 13. One nano-micro column 13 is arranged on each side support arm 12 of the semi-surrounding structure. The method for trimming the bulk sample 35 into a semi-enclosed structure is as follows: a small piece of diamond 4 is cut into a notch 11 by a block-shaped sample 35 by using a focused ion beam, the portion of the sample 35 on both sides of the notch 11 forms the side arms 12, and the portion of the sample 35 between the side arms 12 forms the connecting arm 1.
In one specific embodiment, the bulk sample 35 of the semi-enclosed structure is U-shaped, and the thickness of the semi-enclosed structure is 200 nm; the free end of each support arm of the U shape is provided with a nanometer microcolumn 13, and each nanometer microcolumn 13 is a cylinder with the diameter of 200 nm.
The diamond nano-micro column 13 sample prepared by the invention has regular and controllable shape, surface fluctuation with the height of only a few atomic steps and high surface quality, and the surface precision of the diamond sample can be displayed by electron microscope photos shown in figures 6 and 7.
The invention shown and described herein may be practiced in the absence of any element or elements, limitation or limitations, which is specifically disclosed herein. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, and it is recognized that various modifications are possible within the scope of the invention. It should therefore be understood that although the present invention has been specifically disclosed by various embodiments and optional features, modification and variation of the concepts herein described may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.

Claims (9)

1. The method for manufacturing the pressure head for the transmission electron microscope in-situ pressure test is characterized by comprising the following steps of: the method comprises the following operations: obtaining a base rod, selecting a diamond particle, fixing the diamond particle at the end part of the base rod, exposing a diamond area of a pressure head to be processed, and cutting a cylinder with the diameter of 5-20 mu m in the exposed area of the diamond by using FIB; the cylinder was made perpendicular to the FIB ion beam, and the pressure plane of the cylinder was machined.
2. The method of making an indenter for a transmission electron microscopy in situ pressure test as claimed in claim 1, wherein: firstly, a femtosecond laser is used for processing a boss with the diameter of 10-50 mu m on an exposed area of the diamond, and then a cylinder with the diameter of 5-20 mu m is processed by FIB.
3. The method of making an indenter 34 for transmission electron microscopy in situ pressure testing as claimed in claim 1 or 2, wherein: the reserved area is concentric with the base rod during FIB and/or femtosecond laser processing.
4. The method of making an indenter for a transmission electron microscopy in situ pressure test as claimed in claim 1, wherein: after the matrix is obtained, a pit is dug at the end part of the matrix, the pit is aligned with the matrix, the diamond particle part is placed in the pit, and the diamond particles outside the pit are exposed.
5. The method for manufacturing an indenter for a transmission electron microscopy in-situ pressure test, according to claim 4, wherein: the pits are ball and socket, cylindrical pits, conical pits, or pits matching the diamond particles.
6. The method for manufacturing an indenter for a transmission electron microscopy in-situ pressure test, according to claim 4, wherein: the fixing scheme of the diamond and the substrate is as follows: obtaining a substrate with a pit at the end part, or processing a pit at the end part of the substrate, injecting glue into the pit, then placing diamond particles into the pit, and fixing and maintaining the positions of the diamond particles until the glue is solidified; alternatively, the diamond particles may be fixed to the substrate by means of holding the gemstone by means of claw setting, band setting, or the like.
7. A pressure head for TEM normal position pressure test, its characterized in that: the pressure head comprises a rod-shaped substrate and a diamond particle fixed at the end of the substrate, wherein a cylindrical protrusion with the diameter of 5-20 mu m is arranged in an exposed area of the diamond particle exposed out of the substrate, and the end face of the cylindrical protrusion is formed by FIB processing.
8. An indenter for use in transmission electron microscopy in situ pressure testing as claimed in claim 7, wherein: the cylindrical protrusion of the pressure head is coaxial with the base body.
9. An indenter for use in transmission electron microscopy in situ pressure testing as claimed in claim 8, wherein: the substrate is provided with a pit for containing diamond particles, and the diamond particles are partially embedded into the pit; the diamond particles are fixedly bonded with the substrate, or the diamond particles and the substrate are fixedly embedded by claws or by wrapping.
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