A method for preparing transmission electron microscopy samples of a single-point diamond tool cutting edge

Abstract

This invention belongs to the field of ultra-precision machining technology and discloses a method for preparing transmission electron microscopy (TEM) samples of single-point diamond tool cutting edges. By depositing a Pt protective layer at the wear area of ​​the cutting edge, the damage to the surface morphology of the notch during focused ion beam (FIP) cutting is reduced, thus preparing TEM samples that allow simultaneous observation of the surface morphology and internal defects of the cutting edge. The method includes steps such as sample pretreatment, sample placement, applying a protective layer, etching the sample, transferring the sample, and thinning the sample. This invention, by introducing a Pt protective layer during focused ion beam processing, reduces the damage to the surface morphology of the notch during sample cutting, thus preparing TEM samples that allow simultaneous observation of the surface morphology and internal defects of the cutting edge. The method of this invention can effectively protect the sample surface morphology while simultaneously characterizing internal defects of the cutting edge, and has significant application value.

Description

Technical Field

[0001] This invention belongs to the field of ultra-precision machining technology, and in particular relates to a method for preparing transmission electron microscopy samples of a single-point diamond tool cutting edge. Background Technology

[0002] Nanoscale sharp diamond tools, fundamental tools for ultra-precision machining, undergo shape changes and internal defects on their cutting edges due to wear after cutting. Characterizing their microstructure is crucial for optimizing diamond tool performance and determining their lifespan. Scanning electron microscopy (SEM) is widely used for characterizing tool edges because it can characterize a wide variety of samples, clearly observe fine structures, and does not damage or contaminate the sample during observation. However, its main drawback is its inability to characterize internal defects on the tool edge. Achieving this requires the use of transmission electron microscopy (TEM). TEM is an important characterization technique in materials research, offering high spatial and temporal resolution and the ability to acquire crystallographic information about materials. Using TEM requires the electron beam to penetrate thin samples perpendicularly, necessitating sample preparation.

[0003] Currently, the main method for sample preparation is focused ion beam micro-nano cutting (FIB). This method uses a high-energy ion beam to cut the sample through physical collision, which inevitably causes damage to the sample surface. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing transmission electron microscopy samples of a single-point diamond tool cutting edge, so as to solve the technical problem that it is impossible to simultaneously observe the surface morphology and internal defects of the cutting edge.

[0005] To solve the above-mentioned technical problems, the specific technical solution of the transmission electron microscopy sample preparation method for a single-point diamond tool cutting edge according to the present invention is as follows:

[0006] A method for preparing a transmission electron microscopy (TEM) sample of a single-point diamond tool cutting edge, comprising the following steps:

[0007] Step 1: Sample pretreatment: The worn diamond tool cutting edge is treated with gold spraying to obtain the initial sample;

[0008] Step 2: Place the sample: Attach the initial sample to the sample holder with conductive adhesive, ensuring that the cutting edge faces upwards and the front and rear cutting faces form the same angle with the vertical plane;

[0009] Step 3: Apply protective layer: At zero tilt angle, locate the sample cutting edge notch in the ion beam window and rotate it to horizontal position. Tilt the sample stage so that one cutting edge is parallel to the ion beam and deposit a platinum (Pt) protective layer in the notch area of ​​the other cutting edge.

[0010] Step 4: Etching the sample: At zero tilt angle, find the notch of the sample cutting edge in the ion beam window and rotate it until the cutting edge is perpendicular. Tilt the sample stage so that the cutting edge is viewed from above in the ion beam window. Focus the ion beam under current to remove the diamond in the adjacent areas above and below the protective layer to obtain the original thin sheet sample.

[0011] Step 5: Transfer sample: Rotate to zero tilt angle, extend the easylift needle to contact the thin sample, and use platinum to bond the needle to the sample. Finally, completely sever the connection with the tool at the bottom of the thin sample.

[0012] Step 6: Thinning the sample: The original thin sheet sample is transferred to a vertical focused ion beam. Under current, the damaged areas on the front and back surfaces of the original rectangular thin sheet sample are removed to reduce its thickness to 400 nm. Further, the focused ion beam trims the front and back surfaces of the thin sheet sample under current to reduce its thickness to 150 nm. The focused ion beam voltage is reduced, and the amorphous layer of the thinned overall sample is purged to obtain the final sample.

[0013] Furthermore, in step 3, the platinum protective layer has a 5μm*20μm rectangular shape and a thickness of 0.5μm.

[0014] Furthermore, in step 4, the focused ion beam removes the diamond in the adjacent areas above and below the protective layer under a voltage of 30KV and a current of 65nA.

[0015] Furthermore, in step 6, the focused ion beam removes the damaged areas on the front and back surfaces of the original rectangular thin-film sample under a voltage of 30KV and a current of 0.43nA.

[0016] Furthermore, in step 6, the focused ion beam trims the front and back surfaces of the thin-film sample at a voltage of 30KV and a current of 40pA, reducing its thickness to 150nm.

[0017] Furthermore, in step 6, the focused ion beam voltage is reduced to 5KV, and the thinned whole sample is purged with a current of 41pA for 20nm.

[0018] The transmission electron microscopy (TEM) sample preparation method for a single-point diamond tool cutting edge of the present invention has the following advantages: The present invention proposes a method for preparing worn diamond tool cutting edge samples using focused ion beam (FIP) technology. By depositing a Pt protective layer at the wear site, the damage to the notch surface morphology caused by the FIP beam during sample cutting is reduced, thus preparing a TEM sample that allows simultaneous observation of the cutting edge surface morphology and internal defects. The method of the present invention can effectively protect the sample surface morphology while simultaneously characterizing the internal defects of the cutting edge, and has significant application value. Attached Figure Description

[0019] Figure 1This is a schematic diagram showing the horizontal cutting edge and wear notch under an ion beam, with the front and rear cutting faces distributed on the upper and lower sides respectively.

[0020] Figure 2 A schematic diagram showing that the rake face is roughly parallel to the ion beam and a platinum protective layer is deposited in the notch area of ​​the flank face;

[0021] Figure 3 A schematic diagram showing the process of rotating the back face to be roughly parallel to the ion beam and depositing a platinum protective layer in the notch area of ​​the front face;

[0022] Figure 4 A schematic diagram of the ion beam's top-down view of the cutting edge after the platinum protective layer has been applied;

[0023] Figure 5 The cutting edge is rotated to a vertical position to etch and form the original thin sheet sample. The etching is carried out along the upper and lower sides of the platinum protective layer on the surface of the thin sheet sample.

[0024] Figure 6 This is a schematic diagram of the original thin-film sample viewed at an oblique angle by the ion beam after the tilt angle has been reduced to zero.

[0025] Figure 7 A flowchart illustrating the transfer of the original thin-film sample from the cutting tool to the semi-copper mesh;

[0026] Figure 8 This is a schematic diagram of thinning an original sheet sample on a semi-copper mesh. Detailed Implementation

[0027] To better understand the purpose, structure, and function of this invention, the following detailed description, in conjunction with the accompanying drawings, provides a method for preparing a transmission electron microscope sample of a single-point diamond tool cutting edge according to this invention.

[0028] The present invention provides a method for preparing a transmission electron microscope (TEM) sample of a single-point diamond tool cutting edge, comprising the following steps:

[0029] Step 1, Pre-treat the sample: such as Figure 1 As shown, the horizontal cutting edge and wear notch under ion beam are distributed on the upper and lower sides, respectively. The worn diamond tool cutting edge is then treated with gold sputtering to obtain the initial sample.

[0030] Step 2, Sample Placement: Attach the initial sample to the sample stage using conductive adhesive, ensuring the cutting edge faces upwards and the front and rear cutting faces form approximately the same angle with the vertical plane. Simultaneously place the FIB fixture holding the semi-copper mesh and the sample stage with the initial sample attached into the FIB chamber's sample stage, evacuate the vacuum, and then open the FIB.

[0031] Step 3: Apply a protective layer: At zero tilt angle, locate the sample cutting edge notch in the ion beam window and rotate it until the cutting edge is approximately horizontal. Tilt the sample stage so that one cutting edge is approximately parallel to the ion beam, and deposit platinum (pt) in the notch area of ​​the other cutting edge, forming a 5μm * 20μm rectangle with a thickness of 0.5μm. Repeat the above steps to cover the notch and the adjacent front and rear cutting edges with a platinum protective layer. Figure 2 As shown, the rake face is approximately parallel to the ion beam and a platinum protective layer is deposited. After completion, the tilt angle is zeroed and the sample stage is rotated 180°, as shown. Figure 3 As shown, the blade is rotated so that the back face is approximately parallel to the ion beam, and a platinum protective layer is deposited in the notch region of the front face. Figure 4 As shown, this is the top-down view of the cutting edge after the protective layer has been applied. A protective layer covers the notch and the adjacent front and rear cutting surfaces.

[0032] Step 4, Etching the sample: such as Figure 5 As shown, at zero tilt angle, locate the sample cutting edge notch in the ion beam window and rotate it until the cutting edge is perpendicular. Tilt the sample stage so that the focused ion beam is looking down at the cutting edge (52°), at which point the platinum protective layer is horizontal in the ion beam image. The focused ion beam, at a voltage of 30 kV and a current of 65 nA, removes the diamond in the adjacent areas above and below the protective layer, leaving a sample under the protective layer, thus obtaining the original thin-film sample.

[0033] Step 5, Transfer the sample: (e.g.) Figure 6 As shown, rotating to zero tilt angle allows for a slanted view of the original thin-film sample through the ion beam window. Most of the diamond material is removed from the bottom of the thin-film sample where it connects to the diamond tool, but not completely severed. (See image below.) Figure 7 As shown, extend the easylift needle to contact the sheet sample, and use platinum to bond the easylift needle to the sample. Finally, completely sever the connection between the sample and the tool and retract the easylift needle. The original sheet sample is then adhered to the semi-copper mesh.

[0034] Step 6, thin the sample: such as Figure 8 As shown, the original thin-film sample was transferred to a focused ion beam (FIP) viewing position. Damaged areas on the front and back surfaces of the original rectangular thin-film sample were removed under a voltage of 30 kV and a current of 0.43 nA, reducing its thickness to approximately 400 nm. Further, the FIP beam was used to trim the front and back surfaces of the thin-film sample under a voltage of 30 kV and a current of 40 pA, reducing its thickness to approximately 150 nm. The FIP beam voltage was then reduced to 5 kV, and a current of 41 pA was used to purge the thinned sample for 20 nm to reduce the surface amorphous layer. The final sample was obtained.

[0035] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A method for preparing a transmission electron microscopy sample of a single-point diamond tool cutting edge, characterized in that, Includes the following steps: Step 1: Sample pretreatment: The worn diamond tool cutting edge is treated with gold spraying to obtain the initial sample; Step 2: Place the sample: Attach the initial sample to the sample holder with conductive adhesive, ensuring that the cutting edge faces upwards and the front and rear cutting faces form the same angle with the vertical plane; Step 3: Apply protective layer: At zero tilt angle, locate the sample cutting edge notch in the ion beam window and rotate it to horizontal position. Tilt the sample stage so that one cutting edge is parallel to the ion beam and deposit a platinum (Pt) protective layer in the notch area of ​​the other cutting edge. Step 4: Etching the sample: At zero tilt angle, find the sample cutting edge notch in the ion beam window and rotate it until the cutting edge is perpendicular. Tilt the sample stage so that the cutting edge is viewed from above in the ion beam window. Focus the ion beam under current to remove the diamond in the adjacent areas above and below the protective layer to obtain the original thin sheet sample. Step 5: Transfer sample: Rotate to zero tilt angle, extend the easylift needle to contact the thin sample, and use platinum to bond the needle to the sample. Finally, completely sever the connection with the tool at the bottom of the thin sample. Step 6: Thinning the sample: The original thin sheet sample is transferred to a vertical focused ion beam. Under low current, the damaged areas on the front and back surfaces of the original rectangular thin sheet sample are removed to reduce its thickness to 400 nm. Further, the focused ion beam trims the front and back surfaces of the thin sheet sample under current to reduce its thickness to 150 nm. The focused ion beam voltage is reduced, and the amorphous layer of the thinned overall sample is purged to obtain the final sample.

2. The method according to claim 1, characterized in that, In step 3, the platinum protective layer has a 5μm*20μm rectangular shape and a thickness of 0.5μm.

3. The method according to claim 1, characterized in that, In step 4, the focused ion beam removes the diamond in the adjacent areas above and below the protective layer under a voltage of 30KV and a current of 65nA.

4. The method according to claim 1, characterized in that, In step 6, the focused ion beam removes the damaged areas on the front and back surfaces of the original rectangular thin-film sample under a voltage of 30KV and a current of 0.43nA.

5. The method according to claim 1, characterized in that, In step 6, the focused ion beam trims the front and back surfaces of the thin film sample at a voltage of 30KV and a current of 40pA, reducing its thickness to 150nm.

6. The method according to claim 1, characterized in that, In step 6, the focused ion beam voltage is reduced to 5KV, and the thinned whole sample is purged with a current of 41pA for 20nm.

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