Preparation method and detection method of metallographic specimen

Abstract

The invention discloses a metallographic specimen preparation method and a metallographic specimen detection method, an initial metal specimen is obtained, and the peripheral side of the initial metal specimen is provided with a coating; sleeving the peripheral side of the initial metal sample with metal foil paper to obtain a to-be-treated metal sample; and the to-be-treated metal sample is subjected to post-treatment, and a target metal sample is obtained. The metal foil paper sleeves the outer side of the plating layer of the initial metal sample, so that the problem of shrinkage inconsistency caused by thermal expansion coefficient difference between the plating layer and the plastic in the subsequent thermosetting plastic inlaying process can be relieved, and the formation of interface gaps is reduced; and the risk of warping, fragmentation or stripping of the plating layer in the grinding and polishing process is obviously reduced.

Description

Technical Field

[0001] The present application relates to the field of metal retrieval technology, and in particular to a method for preparing a metallographic sample and a method for detecting the same. Background Art

[0002] During metallographic analysis, sample preparation is a critical step that influences the accuracy of the final analysis results. This is especially true for samples with surface coatings. Effectively protecting the integrity of the coating during cutting, mounting, grinding, and polishing is a major technical challenge. Currently, conventional metallographic sample preparation methods typically use thermosetting plastics to mount the sample to enhance its mechanical strength and facilitate subsequent manipulation.

[0003] However, this method has obvious defects when processing specimens with coatings: the coating and thermosetting plastic shrink at different rates during cooling, resulting in an inability to fit tightly between the two, thus forming gaps or stress concentration areas at the interface, which can easily cause problems such as coating warping, cracking, and even peeling during the subsequent grinding and polishing process. Summary of the Invention

[0004] The embodiments of the present application provide a method for preparing a metallographic sample and a method for detecting the same, which can solve at least one of the above-mentioned technical problems.

[0005] In a first aspect, an embodiment of the present application provides a method for preparing a metallographic sample, comprising: Obtaining an initial metal sample, wherein a peripheral side of the initial metal sample has a plating layer; Sheathing metal foil around the initial metal sample to obtain a metal sample to be processed; The metal sample to be processed is post-processed to obtain a target metal sample.

[0006] In some embodiments, the metal foil is tin foil or aluminum foil.

[0007] In some embodiments, the post-processing includes hot mounting and grinding and polishing, and the post-processing of the metal sample to be processed to obtain a target metal sample includes: Performing a hot mounting process on the metal sample to be processed to obtain a mounted metal sample; The inlaid metal sample is ground and polished to obtain a target metal sample.

[0008] In some embodiments, the end of the metal sample to be processed has a surface to be tested, and the step of subjecting the metal sample to be processed to a hot mounting process to obtain a mounted metal sample comprises: Placing the metal sample to be processed in a preset hot mounting device with the surface to be tested facing downward; The preset hot embedding equipment is used to hot embed the thermosetting plastic on the peripheral side of the metal sample to be processed to obtain an embedded metal sample.

[0009] In some embodiments, obtaining an initial metal sample includes: Obtaining metal blanks to be processed; Cutting the metal blank to be processed for the first time to obtain two sub-blanks; One of the two sub-blanks is selected for a second cutting to obtain the initial metal sample; wherein the initial metal sample forms a first cutting surface during the first cutting, and the initial metal sample forms a second cutting surface during the second cutting, and the second cutting surface is the surface to be measured.

[0010] In some embodiments, after the metal foil is sheathed around the circumference of the initial metal sample, the method further comprises: Flattening the metal foil to obtain a flattened metal sample to be processed; The post-processing of the metal sample to be processed to obtain a target metal sample comprises: The flattened metal sample to be processed is post-processed to obtain a target metal sample.

[0011] In a second aspect, an embodiment of the present application further provides a method for detecting a metallographic sample, wherein a target metal sample obtained by the metallographic sample preparation method according to any of the above embodiments is used for detection, and the detection method comprises: Acquire a first thickness image and a second thickness image of the target metal sample under a microscope; The coating thickness of the target metal sample is obtained based on the first thickness image and the second thickness image.

[0012] In some embodiments, obtaining the coating thickness of the target metal sample based on the first thickness image and the second thickness image includes: determining a first thickness average of the first thickness image and a second thickness average of the second thickness image; The coating thickness of the target metal sample is obtained according to the first average thickness and the second average thickness.

[0013] In some embodiments, determining a first thickness average value of the first thickness image includes: Selecting a preset number of first target points from the first thickness image; determining the coating thickness at each of the first target points; Obtaining a first thickness average value of the first thickness image based on the coating thicknesses of all the first target points; and Determining a second thickness average value of the second thickness image includes: selecting a preset second target point from the second thickness image; determining the coating thickness at each of the second target points; A second thickness average value of the second thickness image is obtained based on the coating thicknesses of all the second target points.

[0014] In some embodiments, after determining the coating thickness of each first target point, the method further includes: determining in sequence whether the coating thickness at each of the first target points meets a preset thickness variation requirement; If the coating thickness of the first target point meets the preset thickness variation requirement, the first target point is used as the first target point to be processed; If the coating thickness of the first target point does not meet the preset thickness variation requirement, the first target point is deleted; Obtaining a first thickness average value of the first thickness image based on the coating thicknesses of all the first target points to be processed; and After determining the coating thickness of each second target point, the method further includes: determining in sequence whether the coating thickness at each of the second target points meets a preset thickness variation requirement; If the coating thickness of the second target point meets the preset thickness variation requirement, the second target point is used as the second target point to be processed; If the coating thickness of the second target point does not meet the preset thickness variation requirement, the second target point is deleted; Based on the coating thicknesses of all the second target points to be processed, a second thickness average value of the second thickness image is obtained.

[0015] In the metallographic sample preparation and testing methods provided in the embodiments of the present application, an initial metal sample is obtained, wherein the initial metal sample has a coating on its circumference; a metal foil is placed around the circumference of the initial metal sample to obtain a metal sample to be processed; and the metal sample to be processed is post-processed to obtain a target metal sample. By placing the metal foil around the coating on the initial metal sample, the shrinkage discrepancy caused by the difference in thermal expansion coefficient between the coating and the plastic can be alleviated during the subsequent thermosetting plastic inlay process, thereby reducing the formation of interfacial voids and significantly reducing the risk of warping, cracking, or peeling of the coating during the polishing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0017] Figure 1 A schematic flow chart of the method for preparing a metallographic sample provided in an embodiment of the present application.

[0018] Figure 2 A schematic flow chart of a method for preparing a metallographic sample according to another embodiment of the present application.

[0019] Figure 3 A schematic flow chart of the metallographic specimen detection method provided in an embodiment of the present application.

[0020] Figure 4 This is a schematic diagram of a metallographic image of the metallographic sample provided in the embodiment of the present application taken under a microscope.

[0021] Figure 5 This is a schematic diagram of a metallographic image of a traditional metallographic specimen taken under a microscope.

[0022] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of this application clearer, the following part will further describe the embodiments of this application in detail with reference to the accompanying drawings.

[0024] When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application, as detailed in the appended claims.

[0025] In the description of this application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances. In addition, in the description of this application, unless otherwise specified, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the relevant listed items.

[0027] During metallographic analysis, sample preparation is a critical step that influences the accuracy of the final analysis results. This is especially true for samples with surface coatings. Effectively protecting the integrity of the coating during cutting, mounting, grinding, and polishing is a major technical challenge. Currently, conventional metallographic sample preparation methods typically use thermosetting plastics to mount the sample to enhance its mechanical strength and facilitate subsequent manipulation.

[0028] However, this method has obvious defects when processing specimens with coatings: the coating and thermosetting plastic shrink at different rates during cooling, resulting in an inability to fit tightly between the two, thus forming gaps or stress concentration areas at the interface, which can easily cause problems such as coating warping, cracking, and even peeling during the subsequent grinding and polishing process.

[0029] For this reason, see Figure 1 The embodiment of the present application provides a method for preparing a metallographic sample, which aims to solve the technical defects in the prior art in that, during the process of preparing a metal sample with a coating, the coating is prone to warping, breaking or peeling, thereby affecting the metallographic observation effect and the accuracy of film thickness measurement.

[0030] See also Figure 1 The method for preparing a metallographic sample includes step 100, step 200 and step 300.

[0031] Step 100: Obtain an initial metal sample, wherein a peripheral side of the initial metal sample has a plating layer.

[0032] The initial metal sample is a metal sample to be subjected to metallographic analysis, and a coating is provided on its circumferential surface. The initial metal sample is usually obtained by cutting the metal component to be tested with a metallographic cutting machine. Its shape and size can be adjusted according to actual testing requirements, such as cylindrical, block or strip shape. The coating is covered on the circumferential surface of the initial metal sample to enhance the corrosion resistance and wear resistance of the base material or improve its surface properties. The coating material can be selected from one or more combinations of common electroplated metals such as nickel, chromium, zinc, tin, etc., and is suitable for different types of metal substrates, such as steel, copper, aluminum and their alloys.

[0033] In this embodiment, the initial metal sample acquisition process includes, but is not limited to, pre-processing operations such as cutting, cleaning, and preliminary polishing of the original metal component to remove oil, scale, and other impurities from the sample surface, ensuring a clear and contamination-free interface between the coating and the substrate, and providing a good foundation for subsequent preparation processes. The pre-processed initial metal sample should have a regular shape and stable structure to facilitate subsequent wrapping with metal foil and inlaying with thermosetting plastic.

[0034] Step 200: Metal foil is placed around the initial metal sample to obtain a metal sample to be processed.

[0035] Metal foil is placed around the periphery of the initial metal sample to form the metal sample to be processed. The metal foil is tightly wrapped around the outer surface of the initial metal sample, especially covering the plated area, to provide buffering, isolation, and protection during subsequent processing. The metal foil is preferably tin foil or copper foil, which has excellent ductility, thermal stability, and thermal conductivity. It maintains structural integrity during the subsequent heating and mounting process and maintains a good bond with the plated surface.

[0036] During the specific implementation process, the metal foil is cut to an appropriate size to completely wrap the circumference of the initial metal specimen, leaving no gaps, wrinkles, or overlaps, ensuring uniformity and stability of the wrapping layer. The wrapping operation can be performed manually at room temperature or automatically with the aid of a fixture or mold to improve wrapping efficiency and consistency. After wrapping, the metal specimen to be processed is coated with metal foil, ready for subsequent thermosetting plastic embedding.

[0037] In this way, by setting metal foil on the outside of the coating, the shrinkage inconsistency problem caused by the difference in thermal expansion coefficient between the coating and the thermosetting plastic during the inlay cooling process can be effectively alleviated, thereby reducing the generation of interface gaps, improving the bonding stability between the coating and the plastic, and laying the foundation for coating protection in the subsequent grinding and polishing process.

[0038] In addition, the metal foil is directly manually placed on the outside of the coating without adding an additional chemical process to place the metal foil on the outside of the coating. The operation is convenient and simple, and the cost is reduced.

[0039] Step 300: Post-process the metal sample to be processed to obtain a target metal sample.

[0040] The foil-wrapped metal sample undergoes post-processing to obtain a target metal sample suitable for metallographic observation. This post-processing includes, but is not limited to, standard metallographic preparation processes such as mounting, grinding, and polishing. Each process step is performed sequentially to ensure that the sample surface achieves a mirror-like quality suitable for microscopic observation while preserving the integrity of the coating structure.

[0041] During the specific implementation process, the metal specimen to be processed is first placed in a metallographic mounting machine and mounted using thermosetting plastic under pressure and heat. During the mounting process, the metal foil maintains a tight fit with the coating, effectively mitigating the differential shrinkage caused by the different thermal expansion coefficients of the coating and the plastic, thereby reducing the formation of interfacial voids and improving the overall structural stability of the specimen. After mounting, the resulting cylindrical specimen has a standard size and regular shape, facilitating subsequent manipulation and observation.

[0042] The mounted specimens are then ground. The grinding process involves two stages: coarse and fine grinding, using sandpaper of varying grits to gradually polish the specimen surface to remove surface irregularities and mechanical damage. During this process, metal foil is continuously attached to the outside of the coating, providing a physical barrier and preventing uneven grinding forces from causing wear, curling, or shedding of the coating's edges.

[0043] After grinding, the specimens are further polished using a metallographic grinder and polisher. Polishing is performed using a polishing cloth and slurry to remove minor scratches left by grinding, achieving a mirror-like finish. During this process, the metal foil remains on the coating surface, effectively preventing coating debris from entering the gap between the coating and the plastic, thereby avoiding coating thickness measurement errors and jagged edges caused by debris accumulation.

[0044] Ultimately, the target metal specimen obtained through this post-processing step exhibits a clear, complete coating edge, a strong bond between the coating and the substrate, and no noticeable scratches or damage on the surface. This allows for high-precision microstructure observation and film thickness measurement under a metallographic microscope. The post-processing process employed in this step is highly compatible with existing metallographic equipment, offers ease of operation, and excellent repeatability, significantly improving the preparation quality and analytical efficiency of the coating specimens.

[0045] In some embodiments, the metal foil is selected from tinfoil or aluminum foil. Both tinfoil and aluminum foil are metal materials with good ductility, thermal stability, and thermal conductivity, and can adapt to the process requirements of heating and mounting and cooling and forming during the preparation of metallographic specimens. During the heating and mounting process, the tinfoil or aluminum foil can maintain structural integrity and will not melt, deform, or react adversely with the coating due to temperature increases. During the cooling process, its thermal shrinkage characteristics are closer to those of thermosetting plastics, which helps to reduce the interfacial stress between the coating and the plastic due to the difference in thermal expansion coefficient, thereby reducing the probability of voids or delamination.

[0046] Furthermore, tinfoil and aluminum foil possess a certain degree of mechanical strength and flexibility. When wrapped around the sides of the initial metal specimen, they adhere closely to the coating surface, resisting wrinkling or peeling, providing a stable foundation for coating protection during subsequent grinding and polishing. Furthermore, tinfoil and aluminum foil are widely available, low-cost, and easy to obtain and process, making them suitable for large-scale application.

[0047] In some embodiments, the post-processing includes a hot mounting process and a grinding and polishing process. Step 300 includes steps 310 and 320 .

[0048] Step 310: performing a hot inlay treatment on the metal sample to be processed to obtain an inlaid metal sample.

[0049] The foil-wrapped metal specimen is placed into the mold cavity of a metallographic mounting machine. Thermosetting plastic powder is then added and hot-pressed under heating and pressure. During the hot mounting process, the temperature is typically controlled between 150°C and 180°C, and the pressure is controlled between 20MPa and 40MPa. After a certain period of cooling, the plastic is fully solidified and forms a stable bond with the metal specimen. This process completely encapsulates the metal specimen within the molded plastic matrix, forming a mounted metal specimen with a regular shape and good mechanical strength, facilitating subsequent grinding and polishing operations.

[0050] During the hot mounting process, the metal foil adheres tightly to the outer surface of the initial metal specimen's coating, providing both cushioning and insulation. Due to its excellent thermal conductivity and moderate ductility, the foil maintains a good bond with the coating during heating and cooling, effectively mitigating shrinkage discrepancies caused by differences in thermal expansion coefficients between the coating and the thermosetting plastic. This reduces interfacial voids and enhances the overall structural stability of the specimen.

[0051] Furthermore, the pressure and temperature generated during hot mounting do not damage the metal foil, preserving its physical integrity and ensuring continued protection of the coating during subsequent grinding and polishing. This procedure is simple to perform and highly compatible with existing metallographic preparation equipment, making it suitable for standardized processing of a wide variety of coated specimens.

[0052] Step 320: Grinding and polishing the inlaid metal sample to obtain a target metal sample.

[0053] The inlaid metal specimens obtained by hot mounting are sequentially ground and polished to remove the mechanical damage layer on the surface of the specimens, obtaining a flat, smooth specimen surface suitable for metallographic microscope observation, and finally forming target metal specimens that can be used for coating analysis.

[0054] During the grinding process, the specimen surface is gradually polished using a metallographic grinder and polisher with silicon carbide sandpaper of varying grits. This process typically consists of two stages: coarse grinding and fine grinding. The coarse grinding stage uses sandpaper with a grit of 180 to 320 to remove surface irregularities and burrs generated during the mounting process. The fine grinding stage uses sandpaper with a grit of 600 to 1200 to further reduce surface roughness, smoothing the specimen surface and preparing it for subsequent polishing. During this process, the metal foil is continuously adhered to the outside of the coating, effectively preventing edge wear, curling, or chipping of the coating due to uneven forces during grinding.

[0055] After grinding, polishing is performed. This process uses a metallographic polishing cloth and aluminum oxide or diamond polishing fluid for mechanical polishing, removing fine scratches left by grinding and achieving a mirror-like surface finish. Appropriate pressure and rotational speed are maintained during polishing to ensure that the coating and the substrate are evenly aligned, avoiding any "raised" or "depressed" appearance caused by differences in material hardness. During this stage, the metal foil remains on the coating surface, providing a physical barrier and preventing coating debris from entering the gap between the coating and the plastic. This prevents coating thickness measurement errors and jagged edges caused by debris accumulation.

[0056] The resulting target metal specimens, obtained through the aforementioned grinding and polishing processes, exhibit a clear, complete coating interface, neat, undamaged coating edges, and no noticeable scratches or contamination on the surface. This enables high-precision microstructure observation and film thickness measurement under a metallographic microscope. This process is highly compatible with existing metallographic equipment, offers stable operation and excellent repeatability, significantly improving the preparation quality and analysis efficiency of coating specimens.

[0057] In some embodiments, the end of the metal sample to be processed has a surface to be tested. Step 310 includes step 3111 and step 3112.

[0058] Step 3111: Place the metal sample to be processed in a preset hot mounting device with the surface to be tested facing downward.

[0059] One end of the metal specimen to be processed has a test surface, which serves as the primary area for subsequent metallographic observation and analysis. This surface is typically the flat surface formed by cutting, cleaning, and preliminary processing of the specimen end. During hot mounting, to ensure that the test surface is effectively exposed during subsequent grinding and polishing, and to maintain the integrity of its surface morphology and coating structure, step 310 includes steps 3111 and 3112. Step 3111 involves placing the metal specimen to be processed in a pre-set hot mounting apparatus, with the test surface facing downward.

[0060] In step 3111, the operator steadily places the foil-wrapped metal specimen into the mold cavity of the hot-mounting machine, ensuring that the specimen remains vertical and stable within the mold, with the surface to be tested facing downward and in contact with the mold bottom. This placement helps ensure a full bond between the surface to be tested and the thermosetting plastic during the subsequent hot pressing process, preventing tilting or shifting of the specimen that could lead to uneven mounting or shedding of the coating. Furthermore, placing the surface to be tested facing downward also allows this area to be preferentially exposed during the subsequent grinding process, thereby reducing excess grinding and improving sample preparation efficiency.

[0061] Furthermore, the mold cavity dimensions are tailored to the shape of the metal specimen being processed to prevent displacement or deflection during the heating and pressurizing process, ensuring structural consistency after mounting. During placement, operators also need to check that the metal foil is completely adhered to the specimen to prevent loose wrapping or wrinkles that could affect subsequent mounting.

[0062] Through the above steps, the metal sample to be processed is correctly placed in the hot mounting equipment, which lays a good foundation for the filling and molding of the thermosetting plastic in the subsequent step 3112, and also provides a guarantee for finally obtaining a target metal sample with a complete structure and a clear test surface.

[0063] Step 3112: Using the preset hot embedding equipment, hot embed the thermosetting plastic on the peripheral side of the metal sample to be processed to obtain an embedded metal sample.

[0064] After the metal specimen to be processed is positioned and placed, a pre-set hot-mounting device is used to hot-mount a thermosetting plastic material around the metal specimen to form a stable, regularly shaped mounted metal specimen. Specifically, an appropriate amount of thermosetting plastic powder is added to the mold cavity of the hot-mounting machine, and then the mold is closed and the heating and pressurization process is started. Under process conditions where the heating temperature is controlled at 150°C to 180°C and the pressure is controlled at 20MPa to 40MPa, the thermosetting plastic gradually melts and flows, filling the gap between the metal specimen to be processed and the mold, covering the specimen, and solidifying into shape after cooling.

[0065] During this process, the thermosetting plastic and the metal specimen to be processed are in indirect contact via the metal foil. The metal foil buffers the thermal stress differences between the coating and the plastic during heating and cooling, reducing the formation of interfacial voids and thus improving the stability of the mosaic structure. Furthermore, because the surface to be tested is placed face-down, the thermosetting plastic, constrained by the mold bottom, evenly wraps around the bottom edge of the specimen, ensuring the entire surface is exposed during subsequent grinding, avoiding issues such as missing edges or uneven wrapping.

[0066] After hot pressing, the mold is cooled to a suitable temperature and opened to remove the inlaid metal sample. This inlaid metal sample has a regular shape, usually cylindrical or square, and has good mechanical strength and easy to handle, providing a good foundation for subsequent grinding and polishing.

[0067] Through the above steps, the thermosetting plastic was successfully hot-embedded around the metal sample to be processed, obtaining an embedded metal sample with complete structure and uniform wrapping, which provided a reliable guarantee for the smooth progress of the subsequent sample preparation process.

[0068] In some embodiments, step 100 includes step 110 , step 120 , and step 130 .

[0069] Step 110: Obtain the metal blank to be processed.

[0070] In the present embodiment, the metal stock can be in the form of a plate, a rod, a block or other geometric forms suitable for metallographic analysis, and specific shapes and sizes can be selected according to actual detection requirements. The base material of the metal stock can include but is not limited to common metal materials such as steel, copper, aluminum and alloys thereof, and the coating material can include metal coatings such as nickel, chromium, zinc, tin, etc. with corrosion resistance, wear resistance or decorative functions. The metal stock is usually derived from finished products or semi-finished products that have completed electroplating processes on production lines, or can be test samples after being processed by specific processes, which are representative and analyzable.

[0071] When obtaining metal blanks, ensure that their surface condition is good, the coating is intact and undamaged, and there is no obvious oxidation, oil stains, or mechanical damage. If necessary, the metal blanks can be preliminarily cleaned or decontaminated to remove surface impurities and provide a good material foundation for subsequent cutting, cleaning, and wrapping operations.

[0072] The metal blank obtained in step 110 is used as the initial material for preparing the metallographic specimen, providing a reliable original sample for the subsequent cutting process of the metal blank in step 120, thereby ensuring that the metallographic specimen finally obtained can accurately reflect the true structure and performance of the coating.

[0073] Step 120: performing a first cutting on the metal blank to be processed to obtain two sub-blanks.

[0074] The metal blank obtained in step 110 is subjected to a first cutting operation to obtain two sub-blanks with symmetrical structures and consistent dimensions. This cutting operation is typically performed on a metallographic cutting machine equipped with a coolant system to prevent thermal damage or structural deformation to the coating on the surface of the metal blank caused by frictional heat during the cutting process.

[0075] During the cutting process, the operator first secures the metal blank in the cutting machine's fixture to ensure stability during the cutting process, preventing uneven cut surfaces due to shaking or shifting. The operator then sets the cutting position based on the sample preparation requirements, typically along the blank's longitudinal centerline or at a designated transverse location. The cutting blade is a resin-bonded or diamond-type blade suitable for metal materials to ensure efficient and high-quality cutting surfaces.

[0076] During the cutting process, coolant is continuously sprayed onto the cutting area, effectively reducing the cutting temperature and preventing oxidation, shedding, or structural changes in the metal coating caused by high temperatures. After cutting, two structurally intact, smooth sub-blanks are obtained. Each sub-blank retains the base material and coating structure of the original metal blank, providing a standard sample for subsequent processing and treatment.

[0077] Through this step, the metal blank is reasonably divided into two sub-blanks, which not only improves the material utilization rate, but also provides a basis for the subsequent preparation of multiple metallographic specimens. It also helps to carry out comparative analysis or repeated experiments, and improve the reliability and statistical significance of the test results.

[0078] Step 130: Select one of the two sub-blanks for a second cutting to obtain the initial metal sample; wherein the initial metal sample forms a first cutting surface during the first cutting, and forms a second cutting surface during the second cutting, and the second cutting surface is the surface to be measured.

[0079] One of the two sub-blanks obtained in step 120 is selected for further processing and subjected to a second cutting operation to obtain an initial metal specimen with a clear surface to be tested. This initial metal specimen is used in subsequent sample preparation steps such as foil wrapping, hot mounting, grinding, and polishing, ultimately forming the target metal specimen suitable for metallographic observation.

[0080] During the specific implementation process, the operator secures the selected sub-blank into the fixture of the metallographic cutting machine and performs a second cut along a predetermined direction based on the preset sample size and the position of the surface to be measured. The first cut forms the first cut surface on the sub-blank, which is the flat surface produced during the initial separation of the metal blank. The second cut forms the second cut surface on the sub-blank, which serves as the primary observation area for subsequent metallographic analysis and is the surface to be measured.

[0081] To ensure the quality of the surface being measured, the second cut utilizes the same cutting equipment and cooling methods as the first. Resin-bonded or diamond-cutting blades suitable for metal materials are used to ensure a smooth, burr-free cut surface. Coolant is continuously sprayed into the cutting area to prevent oxidation, shedding, or structural changes in the metal coating caused by localized high temperatures.

[0082] The initial metal specimen obtained through these two cutting operations has a clear first and second cut surface. The second cut surface, serving as the surface to be tested, has a smooth surface and an intact coating, which can truly reflect the microstructural characteristics of the metal coating and provide a reliable material foundation for subsequent sample preparation and analysis. This cutting process not only improves the controllability and repeatability of sample preparation, but also ensures the realization of high-precision metallographic analysis.

[0083] During specimen preparation, a double-cut process is used to obtain the initial metal specimen, with the cut surface formed by the second cut serving as the test surface. Because this cut surface is obtained from a relatively stable sub-blank that has already undergone the first cut, the impact on the coating during cutting is minimal, effectively preventing coating loss or thermal damage caused by a single rough cut. Furthermore, the smoothness and structural integrity of this test surface facilitate the stability of the coating during subsequent hot mounting and polishing processes, further enhancing the accuracy of metallographic testing results.

[0084] See also Figure 2 In some embodiments, the method for preparing a metallographic sample includes step 100a, step 200a, step 300a, and step 400a, wherein step 100a can be implemented with reference to step 100, and step 200a can be implemented with reference to step 200.

[0085] Step 100a: Obtain an initial metal sample, wherein a peripheral side of the initial metal sample has a plating layer.

[0086] Step 200a: Metal foil is placed around the initial metal sample to obtain a metal sample to be processed.

[0087] Step 300a: Flatten the metal foil to obtain a flattened metal sample to be processed.

[0088] After wrapping the metal foil, the foil wrapped around the initial metal specimen is flattened to obtain a flattened metal specimen to be processed. This flattening operation can be performed manually or using tools such as rollers and clamps to ensure that the metal foil adheres tightly to the specimen surface, eliminating wrinkles, hollows, and overlaps, and improving the uniformity and fit of the wrapping layer. This step helps to improve the bond stability between the metal foil and the plastic during the subsequent hot mounting process, preventing problems such as plastic infiltration and uneven wrapping caused by inadequate wrapping during mounting.

[0089] Furthermore, the flattened metal foil is better suited for subsequent hot mounting, grinding, and polishing processes, reducing localized stress concentrations caused by the foil's undulations, further minimizing the risk of the coating chipping or peeling during grinding and polishing. This step is simple to perform and does not require additional specialized equipment.

[0090] Step 400a: post-processing the flattened metal sample to be processed to obtain a target metal sample.

[0091] The flattened metal sample undergoes post-processing to obtain a target metal sample suitable for metallographic microscopy and film thickness measurement. This post-processing includes several standard metallographic preparation steps, such as hot mounting, grinding, and polishing. These steps are performed sequentially to ensure that the sample surface achieves a mirror-like finish and maintains the integrity of the coating structure.

[0092] During the hot mounting process, a flattened metal specimen is placed into the mold cavity of a metallographic mounting machine, and thermosetting plastic powder is added. Then, hot pressing is performed under heat and pressure to fully melt the plastic and envelop the specimen. After cooling and solidification, a regular and stable mounted metal specimen is formed. Because the metal foil is fully flattened and tightly fitted around the specimen, the mounting process effectively mitigates thermal stress differences between the coating and the plastic, reducing interfacial voids and improving the overall specimen bonding strength.

[0093] After hot mounting, the mounted metal specimens are ground. The grinding process involves two stages: coarse and fine grinding. Silicon carbide sandpaper of varying grit sizes is used to gradually polish the specimen surface to remove surface irregularities and mechanical damage. During this process, the metal foil remains attached to the outside of the coating to prevent wear, curling, or chipping of the coating's edges due to uneven grinding forces.

[0094] Polishing is then performed, using a metallographic polishing cloth and aluminum oxide or diamond polishing fluid to mechanically polish the sample surface, removing any residual scratches and achieving a mirror-like finish. During this process, the metal foil continues to provide isolation and protection, preventing plating debris from entering the gap between the plating and the plastic, thus avoiding plating thickness measurement errors and jagged edges caused by debris accumulation.

[0095] The resulting target metal specimens, after undergoing these post-processing steps, exhibit a clear, complete coating interface, neat, undamaged coating edges, and no noticeable scratches or contamination on the surface. This enables high-precision microstructure observation and film thickness measurement under a metallographic microscope. This process is highly compatible with existing metallographic equipment, offers stable operation and excellent repeatability, significantly improving the preparation quality and analysis efficiency of coating specimens.

[0096] See also Figure 3 、 Figure 4 and Figure 5 , Figure 4 The coating thickness of the metallographic specimen provided in the embodiment of the present application is measured under a microscope. Figure 5 It is the coating thickness measured by traditional metallographic specimen under a microscope. Figure 4 and Figure 5 The darker part is thermosetting plastic. Figure 5 The outer edge of the coating (the edge where the coating is close to the thermosetting plastic) is relatively regular and clear, allowing technicians to measure the thickness of the coating more clearly and accurately. Figure 5 The outer edge of the coating (the edge of the coating close to the thermosetting plastic) is irregular and relatively blurred. This embodiment of the present application also provides a method for testing a metallographic specimen, using a target metal specimen obtained by the metallographic specimen preparation method of any of the above-described embodiments for testing. The metallographic specimen testing method includes steps 400 and 500.

[0097] Step 400: Acquire a first thickness image and a second thickness image of the target metal sample under a microscope.

[0098] The target metal sample obtained after hot mounting, grinding, and polishing is placed under a metallographic microscope for observation, and a first thickness image and a second thickness image are obtained. The first thickness image is an image taken under the microscope of the area with the maximum coating thickness, which is used to analyze the maximum coverage ability and structural uniformity of the coating in a local area; the second thickness image is an image taken under the microscope of the area with the minimum coating thickness, which is used to evaluate whether there are defects such as thinning, plating leakage, or poor bonding in key areas of the coating.

[0099] During the specific implementation process, the operator systematically scans the target metal sample's surface using the microscope's accompanying image acquisition system. Based on the coating thickness distribution trend, the operator determines the locations of the thickest and thinnest coatings. Subsequently, after a preliminary low-magnification observation of the overall coating morphology, high-magnification focused images are taken of the selected thickest and thinnest areas, ensuring that the images clearly reflect the interface characteristics between the coating and the substrate.

[0100] The first thickness image is typically used for macroscopic analysis of the coating's distribution and overall quality, with a magnification typically set at 100x to 200x. The second thickness image is used for precise measurement of the coating's thickness, with a magnification typically set at 500x to 1000x to clearly distinguish the boundary between the coating and the substrate. During image acquisition, brightfield or darkfield illumination is used to enhance the contrast between the coating and the substrate. If necessary, the microscope's automatic measurement function can be used to calibrate and record the coating thickness.

[0101] By obtaining the first thickness image and the second thickness image, not only can the coverage of the coating in different areas be intuitively reflected, but also accurate data basis can be provided for the quantitative analysis and quality judgment of the coating thickness in the subsequent step 500, thereby comprehensively evaluating the process performance and service reliability of the metal coating.

[0102] Step 500: Obtaining the coating thickness of the target metal sample based on the first thickness image and the second thickness image.

[0103] Based on the first thickness image and the second thickness image obtained in step 400, the coating thickness of the target metal sample is measured and analyzed to obtain the coating thickness values ​​of the sample in different areas, and the overall coverage quality and process consistency of the coating are evaluated accordingly.

[0104] During the specific implementation process, the operator processes the first and second thickness images using the image analysis software provided with the metallographic microscope. First, the thickest coating area is identified in the first thickness image. The software automatically or manually selects multiple measurement points, measures the coating thickness at each point, and calculates the average value to obtain a representative thickness value for that area. Then, the thinnest coating area is identified in the second thickness image. Multiple measurement points are measured and the average value is calculated to obtain the minimum thickness value for that area.

[0105] Furthermore, the measurement results are compared with design requirements or industry standards to determine whether the coating meets the predetermined thickness requirements. For example, if the minimum coating thickness is below the lower limit of the process specification, the sample coating is judged to have a risk of local thinning or plating leakage. If the maximum thickness is far above the upper limit of the standard, it may indicate uneven deposition or unstable process control during the electroplating process.

[0106] Furthermore, image data from multiple observation areas can be combined to statistically analyze parameters such as the distribution range and standard deviation of coating thickness, further assessing coating uniformity and process stability. These analysis results can be used to guide optimization and improvement of the coating process, improving product quality and consistency.

[0107] Through the above steps, non-contact, high-precision measurement of the coating thickness of the target metal sample can be achieved based on image information, which not only improves the detection efficiency, but also enhances the repeatability and traceability of the measurement results.

[0108] In some implementations, step 500 includes step 510 and step 520 .

[0109] Step 510: Determine a first average thickness value of the first thickness image and a second average thickness value of the second thickness image.

[0110] First, the first thickness image is analyzed using image processing software. Using an algorithm, the software identifies and calculates the coating thickness values ​​at various measurement points within the first thickness image. The software then aggregates the coating thickness values ​​from all measurement points to calculate the first thickness average. This process ensures accurate measurement of the coating thickness in the thickest area, minimizing the impact of human error.

[0111] The same method is then applied to the second thickness image. The software identifies each measurement point in the second thickness image and records the coating thickness values ​​at those points. Through comprehensive analysis and calculation of these values, the average thickness value for the second thickness image is obtained. This step aims to accurately measure thinner areas and provide a comprehensive understanding of coating thickness variations.

[0112] To improve the reliability of the calculated results, the operator needs to adjust the number and distribution of measurement points based on actual conditions to ensure representative samples. Furthermore, before calculating the average value, the system automatically excludes data points that significantly deviate from the normal range to prevent outliers from influencing the final result. The first and second average thickness values ​​obtained through this processing not only reflect the basic characteristics of the coating thickness but also facilitate further analysis of coating uniformity and process stability in subsequent steps. This step's clear and logically rigorous operational process ensures the scientific and accurate thickness measurement, laying a solid foundation for subsequent quality assessments.

[0113] Step 520: Obtain the coating thickness of the target metal sample according to the first average thickness value and the second average thickness value.

[0114] Based on the first average thickness value and the second average thickness value obtained in step 510 , the coating thickness of the target metal sample is further calculated and determined, thereby achieving a quantitative evaluation of the overall coating coverage performance.

[0115] During implementation, the operator inputs the first and second average thickness values ​​into the data analysis system, which then comprehensively processes the two sets of data based on a pre-set calculation model. Typically, coating thickness is expressed as an average thickness value, calculated by taking the arithmetic mean of the first and second average thickness values. Alternatively, a weighted average or other mathematical method can be used, depending on actual testing requirements, to more accurately reflect the distribution characteristics of the coating across different areas.

[0116] The system also compares the first average thickness with the upper limit of the process standard to determine if the coating is locally too thick. It also compares the second average thickness with the lower limit of the process standard to identify potential defects such as coating thinning, plating defects, or insufficient bonding strength. If any average value exceeds the set tolerance range, the system automatically marks the sample as abnormal and generates a corresponding prompt for further analysis and processing by quality inspection personnel.

[0117] In some embodiments, determining the first thickness average value of the first thickness image includes step 511 , step 512 , and step 513 .

[0118] Step 511: Select a preset first target point from the first thickness image.

[0119] The first thickness image is an image captured under a metallographic microscope of the thickest coating area, reflecting the maximum coating coverage in that local area. The operator processes this image using image analysis software and manually or automatically selects a preset number of first target points within the image. These first target points are typically evenly distributed across areas of thicker coatings, ensuring that the selected measurement points are representative and accurately reflect the coating thickness distribution characteristics in that area.

[0120] During the selection process, the system can use an automatic recognition algorithm to identify clear interfaces between the coating and the substrate in the image and select multiple measurement points within a set range, either evenly spaced or randomly distributed. Alternatively, the operator can manually circle multiple measurement locations based on visual judgment. To enhance the statistical significance of the measurement results, the preset number is typically no less than five, and the specific value can be set based on the inspection standard or process requirements.

[0121] Through the operation of step 511, initial data points for thickness measurement are obtained, which provides a reliable data source for the thickness measurement of each first target point in the subsequent step 512 and the calculation of the average thickness in step 513, thereby improving the accuracy and scientificity of the coating thickness assessment.

[0122] Step 512: Determine the coating thickness of each of the first target points.

[0123] Determine the coating thickness at each of the first target points to provide accurate data support for the subsequent calculation of the first thickness average. This step uses image analysis software to perform detailed measurements of the selected first target points to ensure the accuracy and reliability of the coating thickness data.

[0124] During the specific implementation, the operator first uses the high-resolution image acquisition system associated with the metallographic microscope to acquire a first thickness image and pre-selects multiple first target points within the image (as described in step 511). Next, image analysis software is used to carefully process each first target point to determine the coating thickness. The software automatically measures the distance from the substrate surface to the top of the coating by identifying the interface boundary between the coating and the substrate material, which is the coating thickness at that point.

[0125] To improve measurement accuracy, image analysis software typically uses brightfield or darkfield illumination modes to enhance the contrast between the coating and the substrate, ensuring a clear interface. Furthermore, the software features automatic edge detection, accurately locating the boundary between the coating and the substrate and converting image distances to actual physical dimensions based on pixel scaling. For complex coating structures or multi-layer coatings, the software can perform layered measurements based on the color or reflective properties of the different materials, recording the thickness of each layer separately.

[0126] During the measurement process, the operator must manually verify the results automatically generated by the software to ensure they are correct. For example, in some cases, measurement errors may occur due to image noise or blurred interfaces. In these cases, more accurate data can be obtained by manually adjusting the measurement point position or retaking a higher-resolution image.

[0127] Through the above steps, the software can determine the coating thickness value for each first target point one by one, generating a detailed thickness data list. This data not only reflects the specific thickness distribution of the coating in the thickest area, but also provides a solid foundation for the average value calculation in the subsequent step 513, ensuring that the final first thickness average value is highly representative and accurate.

[0128] Step 513: Based on the coating thicknesses of all the first target points, obtain a first thickness average value of the first thickness image.

[0129] Based on the coating thickness data for all first target points measured in step 512, a first thickness average value of the first thickness image is calculated. This average value reflects the overall thickness level of the target metal specimen in the thickest coating area, providing a quantitative basis for subsequent coating quality assessment and process analysis.

[0130] During implementation, the image analysis system aggregates the coating thickness values ​​for the multiple first target points obtained in step 512 and calculates the first thickness average using an arithmetic mean. Specifically, the system sums the coating thickness values ​​for all first target points and then divides the sum by the total number of measurement points to obtain the average thickness value for the area. In certain embodiments, the system may also employ weighted averaging, median statistics, or a modified average after removing outliers, depending on actual testing requirements, to further enhance the representativeness and reliability of the data.

[0131] To ensure the accuracy of the calculation results, the system verifies the validity of the raw data before executing the calculation. For example, if the thickness value at a particular point deviates significantly from the remaining measurement points and exceeds the preset tolerance range, that point may be identified as an outlier and removed from the calculation to avoid misleading the final results. The system also generates a thickness distribution chart that visually displays the thickness trend at each measurement point, assisting technicians in analyzing the uniformity of the coating.

[0132] In some embodiments, determining the second thickness average value of the second thickness image includes step 514 , step 515 , and step 516 .

[0133] Step 514: Select a preset second target point from the second thickness image.

[0134] Preset second target points are selected from the second thickness image. In this step, the computing system first identifies and locates multiple measurement areas in the second thickness image. Based on a predetermined algorithm or user-defined criteria, the system automatically selects a number of representative second target points for subsequent coating thickness analysis. These second target points are selected to ensure coverage of the entire inspection surface to reflect the overall distribution of coating thickness. To improve data accuracy and representativeness, the selection process takes into account factors such as image resolution, coating uniformity, and potential thickness variation trends.

[0135] During implementation, technicians can adjust parameter settings to specify the number and location of secondary target points. For example, in certain application scenarios, if areas with significant variations in coating thickness require special attention, the density of secondary target points can be increased; whereas, in areas with more uniform coatings, the number of target points can be appropriately reduced. Furthermore, the system supports the manual addition or removal of specific target points, allowing for flexible adjustments for specific situations.

[0136] After selecting the second target points, the system will record the position coordinates of each point and its corresponding preliminary thickness information in preparation for the next step 515. By accurately selecting an appropriate number of second target points, the reliability and accuracy of the final calculated second thickness average value can be effectively improved, thereby providing a solid data foundation for coating quality assessment.

[0137] Step 515: Determine the coating thickness of each of the second target points.

[0138] Determine the coating thickness at each second target point, providing accurate data support for the subsequent calculation of the second thickness average value of the second thickness image. This step uses high-resolution image analysis software to perform detailed measurements of the selected second target points to ensure the accuracy and reliability of the coating thickness data.

[0139] During the specific implementation, the operator first uses the high-resolution image acquisition system associated with the metallographic microscope to acquire a second thickness image and pre-selects multiple second target points within the image (as described in step 514). Next, image analysis software is used to carefully process each second target point to determine the coating thickness. The software automatically measures the distance from the substrate surface to the top of the coating by identifying the interface between the coating and the substrate material, representing the coating thickness at that point.

[0140] To improve measurement accuracy, image analysis software typically uses brightfield or darkfield illumination modes to enhance the contrast between the coating and the substrate, ensuring a clear interface. Furthermore, the software features automatic edge detection, accurately locating the boundary between the coating and the substrate and converting image distances to actual physical dimensions based on pixel scaling. For complex coating structures or multi-layer coatings, the software can perform layered measurements based on the color or reflective properties of the different materials, recording the thickness of each layer separately.

[0141] Specifically, at each secondary target point, the software automatically zooms in and focuses on the interface between the coating and the substrate to ensure accurate measurement results. For example, if the coating is relatively uniform and the interface is clear, the coating thickness is measured directly. If there are multiple coatings or irregular interfaces, the software can use different thresholds or color recognition algorithms to measure the thickness of each layer one by one, and finally summarize the total thickness value.

[0142] During the measurement process, the operator must manually verify the results automatically generated by the software to ensure they are correct. For example, in some cases, measurement errors may occur due to image noise or blurred interfaces. In these cases, more accurate data can be obtained by manually adjusting the measurement point position or retaking a higher-resolution image.

[0143] Step 516: Obtain a second thickness average value of the second thickness image based on the coating thicknesses of all the second target points.

[0144] Based on the coating thickness data for all second target points measured in step 515, a second average thickness value of the second thickness image is calculated. This average value reflects the overall thickness of the target metal specimen in the thinnest coating area, providing a quantitative basis for subsequent coating quality assessment, process optimization, and compliance with technical specifications.

[0145] During implementation, the image analysis system aggregates the coating thickness values ​​for the multiple second target points obtained in step 515 and calculates the average second thickness value using an arithmetic mean. Specifically, the system sums the coating thickness values ​​for all second target points and then divides the sum by the total number of measurement points to obtain the average thickness value for the area. In certain embodiments, the system may also employ weighted averaging, median statistics, or a modified average after removing outliers, depending on actual testing requirements, to further enhance the representativeness and reliability of the data.

[0146] To ensure the accuracy of the calculation results, the system verifies the validity of the raw data before executing the calculation. For example, if the thickness value at a particular point deviates significantly from the remaining measurement points and exceeds the preset tolerance range, that point may be identified as an outlier and removed from the calculation to avoid misleading the final results. The system also generates a thickness distribution chart that visually displays the thickness trend at each measurement point, assisting technicians in analyzing the uniformity of the coating and whether there is localized thinning or plating leakage.

[0147] In some embodiments, after determining the coating thickness of each first target point, the metallographic sample detection method further includes: 1) Determine in sequence whether the coating thickness of each of the first target points meets a preset thickness variation requirement.

[0148] 2) If the coating thickness of the first target point meets the preset thickness variation requirement, the first target point is used as the first target point to be processed.

[0149] 3) If the coating thickness of the first target point does not meet the preset thickness variation requirement, the first target point is deleted.

[0150] 4) Obtaining a first thickness average value of the first thickness image based on the coating thicknesses of all the first target points to be processed.

[0151] Specifically, the coating thickness at each of the first target points is first determined in turn to determine whether it meets a preset thickness variation requirement. These thickness variation requirements are typically based on coating design specifications, process standards, or industry technical indicators, such as a set thickness tolerance range, maximum / minimum thickness thresholds, or relative deviation limits from the average thickness. This determination process can be automated using image analysis software or combined with manual verification to ensure the accuracy of the results.

[0152] If the coating thickness of a certain first target point is within the preset thickness variation range, the first target point will be used as the first target point to be processed, and its thickness data will be retained for subsequent calculations; if the coating thickness of a certain first target point exceeds the preset thickness variation range, the point will be determined as an abnormal point, and the system will delete the first target point from the measurement data set to avoid abnormal data interfering with the final result.

[0153] After all first target points have been screened, the first thickness average value of the first thickness image is calculated based on the coating thickness data of all retained first target points to be processed. This calculation can be performed using an arithmetic mean method, a weighted mean method, or a modified mean method after eliminating extreme values, to further improve the representativeness of the data and the reliability of the calculation results.

[0154] In some embodiments, after determining the coating thickness of each second target point, the metallographic sample detection method further includes: A) determining in sequence whether the coating thickness of each of the second target points meets a preset thickness variation requirement.

[0155] B) If the coating thickness of the second target point meets the preset thickness variation requirement, the second target point is used as the second target point to be processed.

[0156] C) If the coating thickness of the second target point does not meet the preset thickness variation requirement, the second target point is deleted.

[0157] D) obtaining a second thickness average value of the second thickness image based on the coating thicknesses of all the second target points to be processed.

[0158] Specifically, the coating thickness at each of the second target points is first determined in turn to determine whether it meets a preset thickness variation requirement. These thickness variation requirements are typically based on coating design specifications, process standards, or industry technical indicators, such as a set thickness tolerance range, maximum / minimum thickness thresholds, or relative deviation limits from the average thickness. This determination process can be automated using image analysis software or combined with manual verification to ensure the accuracy of the results.

[0159] If the coating thickness of a second target point is within the preset thickness variation range, the second target point will be used as the second target point to be processed, and its thickness data will be retained for subsequent calculations; if the coating thickness of a second target point exceeds the preset thickness variation range, the point will be determined as an abnormal point, and the system will delete the second target point from the measurement data set to avoid interference with the final result caused by abnormal data.

[0160] After all second target points have been screened, the second thickness average value of the second thickness image is calculated based on the coating thickness data of all retained second target points to be processed. This calculation can be performed using the arithmetic mean method, or, depending on actual needs, the weighted mean method or the modified mean method after eliminating extreme values ​​to further improve the representativeness of the data and the reliability of the calculation results.

[0161] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of this application, it should be understood that if the terms "up", "down", "left", "right", etc. indicate directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. This is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting this application. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0162] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for preparing a metallographic sample, characterized in that: include: Obtaining an initial metal sample, wherein a peripheral side of the initial metal sample has a plating layer; Sheathing metal foil around the initial metal sample to obtain a metal sample to be processed; The metal sample to be processed is post-processed to obtain a target metal sample.

2. The method for preparing a metallographic sample according to claim 1, wherein: The metal foil is tin foil or aluminum foil.

3. The method for preparing a metallographic sample according to claim 1, wherein: The post-processing includes hot mounting processing and grinding and polishing processing, and the post-processing of the metal sample to be processed to obtain a target metal sample includes: Performing a hot mounting process on the metal sample to be processed to obtain a mounted metal sample; The inlaid metal sample is ground and polished to obtain a target metal sample.

4. The method for preparing a metallographic sample according to claim 3, wherein: The end of the metal sample to be processed has a surface to be tested, and the metal sample to be processed is subjected to a hot mounting process to obtain a mounted metal sample, comprising: Placing the metal sample to be processed in a preset hot mounting device with the surface to be tested facing downward; The preset hot embedding equipment is used to hot embed the thermosetting plastic on the peripheral side of the metal sample to be processed to obtain an embedded metal sample.

5. The method for preparing a metallographic sample according to claim 4, wherein: The obtaining of the initial metal sample comprises: Obtaining metal blanks to be processed; Cutting the metal blank to be processed for the first time to obtain two sub-blanks; One of the two sub-blanks is selected for a second cutting to obtain the initial metal sample; wherein the initial metal sample forms a first cutting surface during the first cutting, and the initial metal sample forms a second cutting surface during the second cutting, and the second cutting surface is the surface to be measured.

6. The method for preparing a metallographic sample according to claim 1, wherein: After the metal foil is sheathed around the circumference of the initial metal sample, the method further comprises: Flattening the metal foil to obtain a flattened metal sample to be processed; The post-processing of the metal sample to be processed to obtain a target metal sample comprises: The flattened metal sample to be processed is post-processed to obtain a target metal sample.

7. A method for detecting a metallographic sample, characterized in that: The target metal sample obtained by the metallographic sample preparation method according to any one of claims 1 to 6 is tested, and the testing method comprises: Acquire a first thickness image and a second thickness image of the target metal sample under a microscope; The coating thickness of the target metal sample is obtained based on the first thickness image and the second thickness image.

8. The method for detecting a metallographic sample according to claim 7, characterized in that: The obtaining of the coating thickness of the target metal sample based on the first thickness image and the second thickness image includes: determining a first thickness average of the first thickness image and a second thickness average of the second thickness image; The coating thickness of the target metal sample is obtained according to the first average thickness and the second average thickness.

9. The method for detecting a metallographic sample according to claim 8, wherein: Determining a first thickness average value of the first thickness image includes: Selecting a preset number of first target points from the first thickness image; determining the coating thickness at each of the first target points; Obtaining a first thickness average value of the first thickness image based on the coating thicknesses of all the first target points; and Determining a second thickness average value of the second thickness image includes: selecting a preset second target point from the second thickness image; determining the coating thickness at each of the second target points; A second thickness average value of the second thickness image is obtained based on the coating thicknesses of all the second target points.

10. The method for detecting a metallographic sample according to claim 9, characterized in that: After determining the coating thickness of each first target point, the method further includes: determining in sequence whether the coating thickness at each of the first target points meets a preset thickness variation requirement; If the coating thickness of the first target point meets the preset thickness variation requirement, the first target point is used as the first target point to be processed; If the coating thickness of the first target point does not meet the preset thickness variation requirement, the first target point is deleted; Obtaining a first thickness average value of the first thickness image based on the coating thicknesses of all the first target points to be processed; and After determining the coating thickness of each second target point, the method further includes: determining in sequence whether the coating thickness at each of the second target points meets a preset thickness variation requirement; If the coating thickness of the second target point meets the preset thickness variation requirement, the second target point is used as the second target point to be processed; If the coating thickness of the second target point does not meet the preset thickness variation requirement, the second target point is deleted; Based on the coating thicknesses of all the second target points to be processed, a second thickness average value of the second thickness image is obtained.

Images