Preparation method of copper plate EBSD sample

Abstract

The invention discloses a preparation method of a copper plate EBSD sample, and belongs to the technical field of material microscopic analysis and testing. The method mainly comprises the following steps of sample cutting and fixing, gradient abrasive paper grinding, polishing treatment, cleaning and drying, constant-current electrolysis and post-treatment. According to the method, the mechanical damage layer on the surface layer of the sample can be effectively removed, and the strain-free, scratch-free, clean and flat sample surface is obtained, so that the high-quality EBSD Kikuchi pattern is obtained, and the method is suitable for the fields of metal material interface research, tissue analysis, grain boundary characterization and the like.

Description

Technical Field

[0001] This invention belongs to the field of materials microscopic analysis and testing technology, and particularly relates to a method for preparing copper plate EBSD samples. Background Technology

[0002] Electron backscatter diffraction (EBSD) is currently the mainstream method for acquiring information on metallic crystallography, enabling precise characterization of key parameters such as crystal orientation, grain boundary features, texture state, and local strain. Copper and copper alloys, with their excellent electrical and thermal conductivity, are widely used in high-end electronic and electrical devices such as lead frames, radio frequency cavities, and high-permeability shielding components. With the rapid development of 5G and 6G high-frequency, high-speed signal transmission technologies, and the continuously increasing performance requirements of third-generation semiconductor packaging for "low loss and high reliability," the industry's need for detailed crystallographic information on copper plates at the micrometer to submicrometer scale is becoming increasingly urgent. Only by accurately acquiring this information can techniques such as texture optimization and grain boundary engineering be used to effectively reduce material resistivity, suppress electromigration, and reduce warpage. However, copper, as a face-centered cubic (fcc) metal, has inherently soft properties and is highly susceptible to mechanical twinning and oxidation reactions. This directly leads to a low success rate in EBSD sample preparation and poor calibration, thus becoming a core technical bottleneck restricting the accurate characterization of copper plate crystallography. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention proposes a method for preparing copper plate EBSD samples. This method can effectively remove the mechanical damage layer on the sample surface, obtaining a strain-free, scratch-free, clean, and flat sample surface, thereby obtaining high-quality EBSD Kikuchi patterns. This method is applicable to fields such as metal material interface research, microstructure analysis, and grain boundary characterization.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a copper plate EBSD sample includes the following steps: S1. Cut the target sample from the copper material using a cutting or slow sawing method; for irregular or small samples, use a cold inlay process to fix them. S2. Grind the sample surface with sandpaper of decreasing grit size in sequence; S3. Polish the ground sample using diamond or oxide polishing compound; S4. Clean the polished sample and then dry it immediately. S5. Electrolyze the dried sample using an electrolyte solution under constant current. After electrolysis, rinse and dry immediately to obtain the copper plate EBSD sample.

[0005] This invention utilizes a complete process chain of "cutting / embedding - gradient grinding - polishing - cleaning and drying - constant current electrolysis" to synergistically leverage the technical advantages of each step. This effectively addresses the technical bottlenecks of low EBSD sample preparation success rates and poor calibration rates caused by the softness, susceptibility to mechanical twinning, and easy oxidation of copper and copper alloys. It can thoroughly remove the mechanical damage layer and plastic deformation layer from the sample surface, obtaining a strain-free, scratch-free, clean, and smooth sample surface. This significantly improves the signal-to-noise ratio and clarity of EBSD Kikuchi patterns, enhancing EBSD calibration rates and data reliability. It boasts high sample preparation efficiency and is applicable to multiple fields such as metal material interface research, microstructure analysis, and grain boundary characterization, demonstrating strong versatility.

[0006] Furthermore, in step S1, the cutting is performed using a diamond tool.

[0007] Diamond has high hardness and high wear resistance. Using diamond cutting can minimize mechanical damage to the sample surface during the cutting process, avoid the formation of recast layers and tensile stress. Compared with ordinary cutting methods, it can significantly reduce the difficulty of removing the damaged layer in the subsequent grinding process, lay the initial foundation for the preparation of high-quality samples, and ensure that the original tissue state of the sample is not excessively destroyed.

[0008] Furthermore, in step S1, the copper material includes pure copper, brass, or bronze.

[0009] This invention breaks through the limitation of existing sample preparation methods that are only applicable to single-component copper materials, and broadens the scope of application of the preparation method. For copper alloys with different compositions and phases, such as pure copper, brass, and bronze, this method can prepare samples that meet the requirements of EBSD testing. In particular, it can effectively solve the sample preparation problem of multiphase copper alloys, eliminating the need to design separate sample preparation schemes for different copper materials, thus improving the practicality and promotion value of the method.

[0010] Furthermore, in step S1, the insert material used in the cold inlay process is a low-shrinkage, stress-free epoxy resin.

[0011] Epoxy resin has the characteristics of low shrinkage and no stress. When used to fix irregular or small copper samples, it can avoid additional stress and plastic deformation on soft copper samples during the mounting process, ensure that the sample is subjected to uniform force in subsequent grinding, polishing and other processes, stabilize the sample, prevent sample displacement or damage during operation, ensure the stability of the sample preparation process, and thus ensure that the sample test results can truly reflect its original crystallographic characteristics.

[0012] Further, in step S2, the specific operation steps of the grinding are as follows: use sandpaper with a grit size of 80# to 1000# to remove the cutting damage layer; then use sandpaper with a grit size of 1200# to 5000# to gradually refine the surface.

[0013] The gradient grinding design of "coarse grinding to fine grinding" is adopted. The coarse grinding sandpaper from 80# to 1000# can quickly and efficiently remove the thick damage layer and surface impurities generated by cutting, which greatly improves the efficiency of the pre-processing. The fine grinding sandpaper from 1200# to 5000# can gradually refine the sample surface and reduce the scratches generated by coarse grinding. This achieves an orderly transition from "damage removal" to "surface optimization", which not only ensures the grinding effect, but also provides a flat and uniform pre-treated surface for the subsequent polishing process, reducing the polishing difficulty and time cost.

[0014] Furthermore, during the grinding process, after each grinding step, the sample is rotated 90° before the next grinding step, until the scratches generated in the previous step are completely covered and eliminated by the new scratches, thereby ensuring uniform removal of impurities and observing the grinding progress.

[0015] This invention, through a 90° rotation after each grinding step, ensures that all areas of the sample surface are uniformly ground, effectively avoiding problems such as insufficient or excessive grinding in certain areas. At the same time, it allows for direct observation of whether scratches from the previous process have been completely covered and eliminated, facilitating precise control of the grinding progress by operators. It thoroughly removes scratches generated at each stage, preventing residual scratches from affecting subsequent polishing effects and the accuracy of the final EBSD test, thereby improving the controllability of the sample preparation process and the consistency of sample surface quality.

[0016] Further, in step S3, the specific polishing operation steps are as follows: polishing is performed on a lint-free polishing cloth using a diamond suspension with a particle size of 1-3μm for 2-5 minutes to remove the fine scratches generated by fine grinding.

[0017] The diamond suspension with a particle size of 1-3μm has moderate hardness, which can accurately remove the fine scratches produced by fine grinding and is not likely to cause new plastic deformation on the soft copper surface; the lint-free polishing cloth can avoid the problem of mechanical twinning on the copper surface caused by excessively long polishing cloth fibers, or scratch residue caused by excessively short fibers; the polishing time design of 2-5 minutes can ensure that fine scratches are fully removed, while avoiding over-polishing and damage to the sample surface, and finally obtain a smooth, flat and defect-free sample surface, which provides a key guarantee for the formation of high-quality EBSD Kikuchi patterns.

[0018] Furthermore, during the mechanical polishing process, the applied pressure should be light and uniform, preferably 5-15N, to avoid introducing new plastic deformation into the soft copper surface.

[0019] Further, in step S4, the specific steps of the cleaning are as follows: after polishing, the sample is immediately placed in an ultrasonic cleaner and ultrasonically cleaned in anhydrous ethanol for 10 seconds to thoroughly remove the polishing agent and contaminants on the surface; then the sample is immediately dried to avoid water stains and to prevent air oxidation.

[0020] Furthermore, in step S5, the electrolyte is a mixture of nitric acid, methanol, and ethanol in a volume ratio of 1.8:4.5:1.3.

[0021] This specific electrolyte formulation exhibits excellent conductivity and selective corrosion properties, making it precisely compatible with room temperature constant current electrolysis processes. It rapidly and uniformly dissolves the plastic deformation layer and residual impurities on the sample surface, while simultaneously inhibiting the oxidation reaction of copper samples during electrolysis. Compared to electrolytes in existing technologies that easily lead to "orange peel," "cracking," or "oxidation spots," this electrolyte formulation has a wider parameter window and stronger stability. It can effectively avoid sample surface defects caused by improper electrolyte composition, significantly improving the cleanliness and smoothness of the sample surface.

[0022] Furthermore, in step S5, the conditions for constant current electrolysis are: current 1.1A, voltage 7-15V, electrolysis time 15 seconds, and temperature room temperature.

[0023] This invention overcomes the limitations of existing technologies that use low-temperature constant-voltage electrolysis, employing a room-temperature constant-current mode. This eliminates the need for additional low-temperature environments, simplifying sample preparation equipment and procedures, and significantly improving sample preparation efficiency. The optimized combination of 1.1A current, 7-15V voltage, and 15-second time allows for precise control of the electrolysis rate and depth, thoroughly removing the surface plastic deformation layer without damaging the original internal tissue of the sample. The room-temperature environment avoids the influence of low temperature on the sample's tissue state, ultimately significantly improving the resolution of EBSD samples and the clarity of Kikuchi flower patterns, thus enhancing the reliability of the detection data.

[0024] Furthermore, during the constant current electrolysis process, the voltage is 7V.

[0025] This invention strictly controls the voltage variation range during the electrolysis process, effectively avoiding defects such as "orange peel" and "cracking" on the sample surface caused by excessive voltage fluctuations, and ensuring the stability and consistency of the electrolysis process. The 7V voltage is the optimal range for the electrolyte and electrolysis parameters, which can not only ensure the effectiveness of electrolysis, but also inhibit excessive corrosion or oxidation of copper samples, further improving the uniformity and smoothness of the sample surface, ensuring the calibration rate and data repeatability of EBSD detection, and avoiding sample preparation failure due to voltage instability.

[0026] Compared with the prior art, the present invention has the following advantages and technical effects: The method provided by this invention significantly improves the efficiency of sample preparation and effectively removes the damaged layer. Fine mechanical polishing combined with electrolytic polishing thoroughly removes surface plastic deformation, resulting in a strain-free sample surface, laying the foundation for high-quality EBSD analysis. The final sample surface is smooth, scratch-free, clean, and contaminant-free, with extremely low oxidation levels, producing high signal-to-noise ratio and high-resolution Kikuchi patterns, significantly improving the calibration rate and data reliability of EBSD. This method is applicable not only to pure copper but also to various copper alloys such as brass and bronze, and is particularly effective in solving the sample preparation challenges of multiphase copper alloys.

[0027] In the prior art, the electrolysis part of the sample preparation method for copper EBSD samples all uses a low temperature constant pressure method, while the present invention chooses to use a room temperature constant current method for sample electrolysis, which is not only highly efficient, but also improves the resolution. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 The EBSD phase diagram of the copper plate EBSD sample prepared in Example 1; Figure 2 Kikuchi diagram of the copper plate EBSD sample prepared in Example 1; Figure 3 The EBSD phase diagram of the copper plate EBSD sample prepared in Comparative Example 1; Figure 4 Kikuchi diagram of the copper plate EBSD sample prepared in Comparative Example 1; Figure 5 The EBSD phase diagram of the copper plate EBSD sample prepared in Comparative Example 2; Figure 6 Kikuchi diagram of the copper plate EBSD sample prepared in Comparative Example 2. Detailed Implementation

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0030] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0031] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0032] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0033] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0034] This invention provides a method for preparing copper plate EBSD samples, the main route of which is: sample cutting and mounting → mechanical coarse grinding and fine grinding → mechanical polishing → final cleaning and drying → room temperature constant current electrolysis. After electrolysis, the sample is immediately rinsed with anhydrous ethanol and dried. Specifically, the method includes the following steps: S1. Sample Cutting and Mounting: Pure copper, brass, or bronze are selected as the copper material. The target sample is cut from the copper material using diamond wire cutting or slow-speed sawing. Diamond wire cutting can minimize cutting damage. For samples with irregular shapes or small sizes, cold mounting is used for fixation. Low-shrinkage, stress-free epoxy resin is selected as the mounting material during the mounting process to avoid additional stress on the soft copper sample during fixation.

[0035] S2. Mechanical Coarse and Fine Grinding: The sample surface is ground sequentially using sandpaper with decreasing grit. First, coarse grinding is performed using sandpaper with grits ranging from 80# to 1000# (80#, 240#, 400#, 800#, 1000# in sequence) to remove the cutting damage layer from the sample surface. After coarse grinding, fine grinding is performed using sandpaper with grits ranging from 1200# to 5000# (1200#, 1500#, 2000#, 3000#, 5000# in sequence) to gradually refine the sample surface. After each grinding step, the sample is rotated 90° before the next grinding step, until the scratches from the previous grinding step are completely covered and eliminated by the new scratches. This ensures uniform material removal and facilitates observation of the grinding progress.

[0036] S3. Mechanical Polishing: Polish the ground sample using diamond or oxide polishing compound. The specific procedure is as follows: Select a diamond suspension with a particle size of 1-3 μm (e.g., 3 μm) and polish the sample on a lint-free polishing cloth. The polishing time should be controlled at 2-5 minutes (e.g., 5 minutes) to thoroughly remove the fine scratches generated during the fine grinding process. During polishing, the applied pressure should be light and uniform, preferably 5-15 N (e.g., 10 N), to avoid introducing new plastic deformation to the surface of the soft copper sample due to improper pressure.

[0037] S4. Final cleaning and drying: After polishing, immediately place the sample in an ultrasonic cleaner and ultrasonically clean it for 10 seconds in an anhydrous ethanol environment to ensure that the polishing agent and other contaminants remaining on the sample surface are completely removed. After ultrasonic cleaning, immediately blow-dry the sample to prevent water stains from forming on the sample surface and to avoid air oxidation of the sample.

[0038] S5. Room Temperature Constant Current Electrolysis: Prepare the electrolyte by mixing nitric acid, methanol, and ethanol in a volume ratio of 1.8:4.5:1.3. Place the dried sample in this electrolyte for constant current electrolysis. The electrolysis conditions are set as follows: current 1.1A, voltage 7-15V, electrolysis time 15 seconds, and electrolysis temperature maintained at room temperature (15-25℃). A constant current state must be maintained during electrolysis, with an optimal voltage of 7V. After electrolysis, immediately rinse the sample with anhydrous ethanol and then quickly dry it to obtain a qualified copper plate EBSD sample.

[0039] Unless otherwise specified, "room temperature" in this invention refers to 15-25℃.

[0040] All raw materials used in this invention were purchased from the market.

[0041] The technical solution of the present invention will be further illustrated by the following embodiments.

[0042] Example 1 A method for preparing a copper plate EBSD sample includes the following steps: S1. Sample cutting and mounting: Pure copper is selected as the copper material, and a target sample of 5mm×5mm×5mm is cut from the copper material by diamond wire cutting. For samples with irregular shape or small size, cold mounting process is used for fixing. Epoxy resin is used as the mounting material during the mounting process, and the thickness of the mounting material is 10mm. S2. Mechanical Coarse Grinding and Fine Grinding: First, coarse grinding is performed using sandpaper with grits of 80#, 240#, 400#, 800#, and 1000#. Grinding is done gradually from low grit to high grit. Each time, when there are no obvious defects or scratches, the next grit sandpaper is used to continue grinding. The purpose is to remove the cutting damage layer on the sample surface. After coarse grinding, fine grinding is performed using sandpaper with grits of 1200#, 1500#, 2000#, 3000#, and 5000# to gradually refine the sample surface. After each grinding step, the sample is rotated 90° before the next grinding step, until the scratches produced by the previous grinding are completely covered and eliminated by the new scratches. This ensures that the material is removed evenly and facilitates the observation of the grinding progress. S3. Mechanical polishing: Select a diamond suspension with a particle size of 3μm and polish the sample on a lint-free polishing cloth. The polishing time is controlled within 5 minutes to thoroughly remove the fine scratches generated during the fine grinding process. During the polishing process, apply a pressure of 10N to avoid introducing new plastic deformation to the surface of the soft copper sample due to improper pressure. S4. Final cleaning and drying: After polishing, immediately place the sample in an ultrasonic cleaner and ultrasonically clean it for 10 seconds in an anhydrous ethanol environment to ensure that the polishing agent and other contaminants remaining on the sample surface are completely removed; after ultrasonic cleaning, immediately blow-dry the sample to prevent water stains from forming on the sample surface and to avoid air oxidation of the sample. S5. Room temperature constant current electrolysis: Prepare an electrolyte solution by mixing nitric acid, methanol, and ethanol in a volume ratio of 1.8:4.5:1.3. Place the dried sample in the electrolyte solution for constant current electrolysis. Set the electrolysis conditions as follows: current 1.1A, voltage 7V, electrolysis time 15 seconds, and maintain the electrolysis temperature at room temperature. After electrolysis, immediately rinse the sample with anhydrous ethanol and then quickly dry it to obtain a copper plate EBSD sample that meets the requirements.

[0043] Figure 1 The EBSD phase diagram of the copper plate EBSD sample prepared in Example 1 has a resolution of 92.56%.

[0044] Figure 2 The image shows a Kikuchi diagram of the copper plate EBSD sample prepared in Example 1.

[0045] Comparative Example 1 Same as Example 1, except that the voltage is controlled at 5V during the constant current electrolysis process at room temperature.

[0046] Figure 3 The EBSD phase diagram of the copper plate EBSD sample prepared in Comparative Example 1 has a resolution of 88.44%.

[0047] Figure 4 The image shows the Kikuchi diagram of the copper plate EBSD sample prepared in Comparative Example 1.

[0048] Comparative Example 2 A method for preparing copper EBSD samples, the process route is: mechanical grinding - mechanical polishing - electrolytic polishing, the specific steps are as follows: S1. Wire EDM Sampling: A 10mm×10mm×2mm sample is obtained by cutting copper (pure copper) with a slow wire. During the cutting process, due to the high temperature melting of the electric spark and the rapid cooling of the coolant, the molten metal is rapidly solidified before it can vaporize, forming a recast layer. The rapid cooling and shrinkage is constrained by the substrate, which in turn generates tensile stress, introducing a 30μm deep recast layer and tensile stress on the sample surface, which must be removed by grinding and polishing. S2. Multi-pass SiC wet sandpaper polishing: Use 320#→800#→1200#→2000#→4000# sandpaper in sequence for polishing. Rotate 90° in each pass to remove the scratches from the previous pass. Because copper is soft, the polishing particles are easily pressed into the surface to form "embedded particles", which appear as artifacts during EBSD scanning and cause the calibration rate to drop sharply. S3, Diamond polishing: Diamond suspensions with particle sizes of 9μm, 3μm, and 1μm were used for polishing for 5 minutes, 5 minutes, and 5 minutes respectively. The results showed that if the polishing cloth fibers were too long, mechanical twinning would be induced on the copper surface, resulting in local blurring of the Kikuchi pattern; if the polishing cloth fibers were too short, scratches would remain, which would also reduce the calibration rate. S4. Electrolytic Polishing: Prepare an electrolyte solution by mixing H3PO4, C2H5OH, and H2O in a volume ratio of 7:2:1. Place the dried sample in the electrolyte solution for electrolysis. The electrolysis conditions are set as follows: temperature -10℃, voltage 6V, and time 15 seconds. After electrolysis, rinse with deionized water and then dry with cold air. However, it was found that if the rinsing time is more than 10 seconds, oxidation black spots may appear, and if the rinsing time is less than 5 seconds, acid residue will remain, leading to secondary corrosion.

[0049] Figure 5 The EBSD phase diagram of the copper plate EBSD sample prepared in Comparative Example 2 has a resolution of 88.17%.

[0050] Figure 6 Kikuchi diagram of the copper plate EBSD sample prepared in Comparative Example 2.

[0051] Using the process method of Comparative Example 2, the sample preparation success rate is approximately 60-70%, and the calibration rate is 80-85%. However, the following problems also arise: ① The electrolysis parameter window is narrow, and voltage fluctuations of ±0.5V can cause "orange peel" or "pitting"; ② The polarization behavior of high-purity oxygen-free copper (OFHC) differs greatly from that of copper alloys containing silver, chromium, and zirconium, making it difficult to apply the same electrolysis parameters universally; ③ A 2-3nm thick amorphous oxide film is easily formed on the surface after electrolysis, which still leads to a relatively high zero-dissolution rate even under a 20kV beam voltage.

[0052] Comparing the data from Example 1, Comparative Example 1, and Comparative Example 2, it can be seen that the resolution of the copper plate EBSD sample prepared using Example 1 of the present invention is much higher than that of Comparative Example 1 and Comparative Example 2. This indicates that the method of Example 1 not only significantly improves the ease of operation but also produces high-quality EBSD samples with clearly discernible grain boundary contours, excellent first-pass yield and calibration rate, accurate and reliable orientation characterization results, and clear presentation of some fine structures and features. Simultaneously, this method has a good effect on improving the EBSD detection efficiency, optimizing detection quality, and reducing detection costs for copper and copper alloys. Furthermore, compared with schemes using the same method but with different electrolysis parameters, the electrolysis parameters selected in Example 1 are the optimal combination of parameters under the given preparation conditions.

[0053] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method of preparing a copper plate EBSD sample, characterized by, Includes the following steps: S1. Cut the target sample from the copper material using a cutting or slow sawing method; for irregular or small samples, use a cold inlay process to fix them. S2. Grind the sample surface with sandpaper of decreasing grit size in sequence; S3. Polish the ground sample using diamond or oxide polishing compound; S4. Clean the polished sample and then dry it immediately. S5. Electrolyze the dried sample using an electrolyte solution under constant current. After electrolysis, rinse and dry immediately to obtain the copper plate EBSD sample.

2. The method for preparing copper plate EBSD samples according to claim 1, characterized in that, In step S1, the cutting is performed using a diamond tool.

3. The method for preparing copper plate EBSD samples according to claim 1, characterized in that, In step S1, the copper material includes pure copper, brass, or bronze.

4. The method for preparing copper plate EBSD samples according to claim 1, characterized in that, In step S1, the inlay material used in the cold inlay process is epoxy resin.

5. The method for preparing copper plate EBSD samples according to claim 1, characterized in that, In step S2, the specific grinding operation steps are as follows: use sandpaper with a grit size of 80# to 1000# for coarse grinding to remove the cutting damage layer; then use sandpaper with a grit size of 1200# to 5000# for fine grinding to gradually refine the surface.

6. The method for preparing copper plate EBSD samples according to claim 5, characterized in that, During the grinding process, after each grinding step, the sample is rotated 90° before the next grinding step, until the scratches generated in the previous step are completely covered and eliminated by the new scratches.

7. The method for preparing copper plate EBSD samples according to claim 1, characterized in that, In step S3, the specific polishing operation steps are as follows: polishing is performed on a lint-free polishing cloth using a diamond suspension with a particle size of 1-3 μm for 2-5 minutes.

8. The method for preparing copper plate EBSD samples according to claim 1, characterized in that, In step S5, the electrolyte is a mixture of nitric acid, methanol and ethanol in a volume ratio of 1.8:4.5:1.

3.

9. The method for preparing a copper plate EBSD sample according to claim 1, characterized in that, In step S5, the conditions for constant current electrolysis are: current 1.1A, voltage 7-15V, electrolysis time 15 seconds, and temperature room temperature.

10. The method for preparing a copper plate EBSD sample according to claim 9, characterized in that, In step S5, the constant current electrolysis conditions are: current 1.1A, voltage 7V, electrolysis time 15 seconds, and temperature room temperature.

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