Sample preparation method for coating full-thickness tissue display
By measuring the thickness and width of the coating, calculate its inclination, make the inclination cushion, and use these blocks during the mosaic sample. The clear display and accurate analysis of the full thickness tissue of the coating.
Patent Information
- Application Number
- CN202411123095.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-15
- Publication Date
- 2025-01-24
AI Technical Summary
When characterizing and analyzing the structure and phase transition of the coating, the traditional polishing method can only display the coating morphology of a certain thickness, and requires multiple measurements and preparation of samples, which is time-consuming and labor-consuming, and May affect the accuracy of observations.
By measuring the thickness and width of the coating cross section, calculate the angle α between its diagonal and the plane, make pads with an inclination angle α, and use these pads during the inlay and polishing process to ensure that the full thickness of the coating is measured at one time clearly visible in the specimen.
The tissue form of the one -time observation of the full thickness plane of the coating is realized, the thickness of the coating is accurately located, the secondary measurement affects the quality of the coating surface, simplifies the sample preparation process, and improves the accuracy of the observation results.
Smart Images
Figure CN119354668A_ABST
Abstract
Description
Technical Field
[0001] The present invention mainly relates to the "field of metallographic sample preparation technology", "field of coating tissue display technology" and "field of material science research", and specifically to a sample preparation method for coating full-thickness tissue display. Background Art
[0002] Background introduction of related technologies: The operating environment of the hot end components of gas turbine turbines is often very harsh. With the current requirements for improving gas turbine efficiency, the turbine inlet temperature needs to be increased, which requires the use of special coatings on key components for protection in order to improve the reliability of blade service. For example, the surface of gas turbine turbine blades is usually coated with MCrAlY type anti-oxidation corrosion coatings (M refers to Fe, Ni, Co, etc.) or YSZ thermal barrier coatings and other external coatings to improve the stability of the blades in high temperature and thermal corrosion environments. However, these coatings will undergo element diffusion or phase transformation processes during high-temperature service, resulting in different organizational morphologies of the coatings in various thickness directions. The research work needs to characterize and evaluate the organizational structure and phase transformation of the coatings at various heights.
[0003] Solutions of existing technologies: In order to characterize and analyze the organizational morphology and phase transition of the coating, the existing technology mainly prepares the metallographic samples of the coating by epoxy resin embedding, grinding and polishing, and then observes and analyzes the coating structure under a metallographic microscope and a scanning electron microscope. The phase transition and orientation information of the coating can also be analyzed by electron backscatter diffraction (EBSD) technology.
[0004] Problems with existing technologies: However, these existing methods all have some problems. First, the traditional grinding and polishing method can only show the morphology of a coating of a certain thickness, and it is usually necessary to measure the thickness of the coating observation surface after grinding again. Secondly, for EBSD analysis samples, removing them from epoxy resin and measuring the thickness again will affect the surface quality. In addition, the traditional method requires multiple grinding and thickness measurements to observe the changes in the organizational morphology of the coating in each thickness direction, which is not only time-consuming and labor-intensive, but may also affect the accuracy of the observation results due to errors in the sample preparation process. Summary of the invention
[0005] The purpose of the present invention is to provide a sample preparation method for coating full thickness microstructure display, which mainly solves the following problems: 1) the technical problem that the traditional grinding and polishing method can only display the coating morphology of a certain thickness; 2) for EBSD samples, the technical problem that re-measurement will affect the surface quality of the coating; 3) the technical problem that multiple samples need to be prepared to observe the microstructure of the coating in each thickness direction, which is time-consuming and labor-intensive, and the accuracy of the observation results may be affected due to errors in the sample preparation process.
[0006] In order to achieve the above-mentioned purpose, the technical solution of the present invention is:
[0007] A method for preparing a sample for full-thickness structure display of a coating comprises the following steps:
[0008] (1) Measure the thickness h and width w of the coating cross section;
[0009] (2) Calculate the angle α between the diagonal of the coating cross section and the plane;
[0010] (3) Making a cushion block: using an angle measuring ruler or a stepping motor and corresponding tools to make a cushion block with an inclination angle α;
[0011] (4) Inlaid and polished specimens: In the mold to be injected with epoxy resin, a pad with an inclination angle α is placed below the coating surface of the specimen, and then the epoxy resin is poured; during the grinding and polishing process, the additional pad is completely polished away to show the microstructure of the coating in the full thickness plane.
[0012] The sample preparation method for the full-thickness microstructure display of the coating comprises the following steps: in step (1), firstly measuring the surface to be observed of the coating to prepare a cross-sectional sample of the surface to be observed; and then measuring the thickness h of the coating and the width w of the surface to be observed of the coating under a metallographic microscope.
[0013] In the sample preparation method for the full-thickness microstructure display of the coating, in step (2), the measured coating thickness h and width w are used to determine the coating inclination angle α by calculating the formula α=arctan(h / w), and the inclination angle α is used to make a pad for the coating on the sample.
[0014] In the sample preparation method for the full-thickness microstructure display of the coating, in step (3), the pad material is epoxy resin or paraffin, and a pad with an inclination angle α is made using an angle measuring ruler and a splint thereon, ensuring that the shape of the pad matches the inclination angle α of the coating, and maintaining the flatness and parallelism of the pad.
[0015] The sample preparation method for the full-thickness tissue display of the coating, in step (3), the gasket material is epoxy resin or paraffin, a stepper motor is used to make a gasket with an inclination angle α, a movable plate that rotates with the rotating shaft is installed on the rotating shaft of the stepper motor, one end of the horizontal fixed plate corresponds to the end of the movable plate installed on the rotating shaft as the vertex, starting from the overlapping position of the fixed plate and the movable plate, the movable plate rotates to form an angle between the fixed plate and the movable plate, and a gasket with an inclination angle α is made by adjusting the angle between the fixed plate and the movable plate, ensuring that the shape of the gasket matches the inclination angle α of the coating, and maintaining the flatness and parallelism of the gasket.
[0016] The sample preparation method for displaying the full-thickness structure of the coating, in step (4), during the sample embedding process, a pad with an inclination angle α is placed at the bottom of the mold cavity, and the coating surface of the sample is downward and close to the pad with an inclination angle α; during the grinding and polishing process, sandpaper is first used for grinding, and then a polishing machine is used for polishing, so that the full-thickness structure of the coating is clearly visible.
[0017] Compared with the existing technology, the advantages and beneficial effects of the present invention are as follows:
[0018] 1. Observe the organizational morphology of the full-thickness plane of the coating at one time: The present invention can simultaneously observe the changes in the organizational structure and precipitation phase of the full-thickness of the coating by preparing a sample once, while the traditional method needs to prepare multiple samples to observe the organizational morphology of the coating in each thickness direction, which is not only time-consuming and labor-intensive, but may also affect the accuracy of the observation results due to errors in the sample preparation process.
[0019] 2. Accurately locate the coating thickness: The present invention can accurately locate the different coating thicknesses from the substrate surface to the coating surface along the coating cross-section diagonal by calculating the angle α between the coating cross-section diagonal and the plane, thereby more accurately observing and studying the coating's organizational morphology and phase transition in each thickness direction at one time. Traditional methods usually have difficulty determining the coating thickness, which may affect the accuracy of the observation results.
[0020] 3. Avoid secondary measurement affecting the surface quality of the coating: In the process of preparing the sample, the present invention uses a precision angle measuring ruler or a stepping motor to make a pad with an inclination angle α, so that the full thickness of the coating can be displayed without damaging the surface quality of the coating. In general, compared with the prior art, the present invention has the advantages of simple operation, accurate thickness positioning, and one-time observation of the full thickness of the coating plane structure, and is an ideal coating full thickness structure display method. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 Schematic diagram for measuring the inclination angle of the outer coating on the surface of the substrate coating sample.
[0022] Figure 2 Schematic diagram of preparing a pad with an inclination angle of α for an angle measuring ruler.
[0023] Figure 3 Schematic diagram of preparing a pad with an inclination angle of α for a stepper motor.
[0024] Figure 4 Schematic diagram of epoxy-coated specimen and spacer.
[0025] Figure 5 Schematic diagram showing the full-thickness coating morphology after grinding away the pad.
[0026] In the figure, 1 is a sample, 2 is a coating, 3 is an angle measuring ruler, 4 is a spacer, 5 is a mold, 6 is an epoxy resin, 7 is a stepper motor, 8 is a rotating shaft, 9 is a fixed plate, and 10 is a movable plate. DETAILED DESCRIPTION
[0027] Below, the present invention is further described in detail by examples.
[0028] Embodiment 1:
[0029] like Figure 1-Figure 5 As shown, a sample preparation method for coating full thickness structure display comprises the following steps:
[0030] Step 1: If Figure 1 As shown, the thickness (h) and width (w) of the coating cross section are measured. First, we need to measure the surface to be observed of the coating 2, prepare the cross-sectional sample 1 of the surface to be observed, and then measure the thickness (h) of the coating 2 and the width (w) of the surface to be observed of the coating 2 under a metallographic microscope. In this embodiment, we selected a gas turbine turbine blade sample coated with a CoCrAlY-based anti-corrosion coating, and measured the cross section using a metallographic microscope. The thickness (h) of the coating 2 on the surface of the sample 1 was 100 μm, and the width (w) of the surface to be observed of the coating 2 was 1 mm.
[0031] Step 2: Calculate the angle α between the diagonal line of the coating cross section and the plane. Using the measured coating thickness (h) and width (w), the inclination angle α is determined by the calculation formula α=arctan(h / w). In this embodiment, the calculated inclination angle α of the coating 2 is about 5°42′, which will be used to make the pad 4 of the coating 2 on the sample 1.
[0032] Step 3: Make the pad.
[0033] like Figure 2 As shown, a suitable material, such as epoxy resin or paraffin, is selected, and a pad 4 with an inclination angle α is made using a precision angle measuring ruler 3 and a suitable tool. In this embodiment, epoxy resin is selected as the pad material, and a pad 4 with an inclination angle α=5°42′ is made using a precision angle measuring ruler 3 and a clamp thereon, ensuring that the shape of the pad 4 matches the inclination angle α of the coating 2, and maintaining the flatness and parallelism of the pad.
[0034] like Figure 3As shown, a suitable material is selected, such as epoxy resin or paraffin, and a stepper motor 7 and a suitable tool are used to make a cushion block 4 with an inclination angle α. A movable plate 10 that rotates with the rotating shaft 8 is installed on the rotating shaft 8 of the stepper motor 7. One end of the horizontal fixed plate 9 corresponds to the end of the movable plate 10 installed on the rotating shaft 8 as a vertex. Starting from the overlapping position of the fixed plate 9 and the movable plate 10, the movable plate 10 rotates to form an angle between the fixed plate 9 and the movable plate 10. The cushion block with an inclination angle α is made by adjusting the angle between the fixed plate 9 and the movable plate 10. In this embodiment, we selected epoxy resin as the pad material, used a stepper motor 7 with a step angle of 1.8 degrees, set the driver of the stepper motor 7 to 8 subdivisions, so that the step angle of the rotating shaft 8 is 1.8° / 8=0.225°, and the rotation angle when taking 25 steps is 1.8 / 8×25=5°38′, that is, the angle formed between the fixed plate 9 and the movable plate 10 is 5°38′, thereby producing a pad 4 with an inclination angle α=5°38′, ensuring that the shape of the pad 4 matches the inclination angle α of the coating 2, and maintaining the flatness and parallelism of the pad.
[0035] Step 4: Mount and polish the sample. Figure 4-Figure 5 As shown, in the mold 5 to be injected with epoxy resin 6, the prepared pad 4 is placed below the surface of the coating 2 of the sample 1, and then the epoxy resin 6 is poured. During the grinding and polishing process, the additional pad 4 is completely ground off. After the surface of the embedded coating 2 is ground and polished, the full thickness structure of the coating can be displayed. In this embodiment, the prepared pad 4 is placed in the surface of the coating 2, and then the epoxy resin 6 is injected into the mold 5 to ensure that the pad 4 can support the entire coating thickness. We use sandpaper for grinding and then use a polishing machine for polishing so that the full thickness structure of the coating is clearly visible.
[0036] Through the above technical means, the present invention can realize the observation of the organizational changes of the full-thickness plane of the coating through only one metallographic sample preparation, thereby solving the problem that the traditional grinding and polishing method can only display the coating morphology of a certain thickness, and also avoiding the technical problem that for EBSD samples, the re-measurement will affect the surface quality of the coating. At the same time, it also solves the technical problem that multiple samples need to be prepared to observe the organizational morphology of the coating in each thickness direction, which is time-consuming and labor-intensive, and may affect the accuracy of the observation results due to errors in the sample preparation process.
[0037] The implementation results show that the application prospects of the present invention are as follows: Due to the novelty of the technical solution, it can be used in aerospace, gas turbines, petrochemicals, electric power generation and other fields that use coatings for protection. In these fields, various mechanical equipment often need to operate in harsh environments such as high temperature and corrosion, which requires the use of special coatings for protection at key parts to improve their service life and reliability. The metallographic sample preparation method for the full-thickness coating structure display of the present invention can more accurately and comprehensively observe and study the organizational morphology and phase transformation of the coating, thereby providing strong technical support for improving the performance and service life of the coating. In addition, the method of the present invention is simple and easy to implement, which can not only save a lot of time and energy, but also improve the accuracy of the observation results, so it has high practical value and broad market prospects.
Claims
1. A method for preparing samples for full-thickness tissue display of coatings, characterized in that: The steps include: (1) Measure the thickness h and width w of the coating cross section; (2) Calculate the angle α between the diagonal of the coating cross section and the plane; (3) Making a cushion block: using an angle measuring ruler or a stepping motor and corresponding tools to make a cushion block with an inclination angle α; (4) Inlaid and polished specimens: In the mold to be injected with epoxy resin, a pad with an inclination angle α is placed below the coating surface of the specimen, and then the epoxy resin is poured; during the grinding and polishing process, the additional pad is completely polished away to show the microstructure of the coating in the full thickness plane.
2. The sample preparation method for coating full thickness structure display according to claim 1, characterized in that: In step (1), the surface to be observed of the coating is first measured to prepare a cross-sectional sample of the surface to be observed; then the thickness h of the coating and the width w of the surface to be observed of the coating are measured under a metallographic microscope.
3. The method for preparing a sample for full-thickness microstructure display of a coating according to claim 1, characterized in that: In step (2), the measured coating thickness h and width w are used to determine the coating inclination angle α by calculating the formula α=arctan(h / w), and the inclination angle α is used to make a pad for the coating on the sample.
4. The method for preparing a sample for full-thickness structure display of a coating according to claim 1, characterized in that: In step (3), the pad material is epoxy resin or paraffin, and a pad with an inclination angle α is made using an angle measuring ruler and a clamp thereon, ensuring that the shape of the pad matches the inclination angle α of the coating to maintain the flatness and parallelism of the pad.
5. The method for preparing a sample for full-thickness structure display of a coating according to claim 1, characterized in that: In step (3), the pad material is epoxy resin or paraffin, and a stepper motor is used to make a pad with an inclination angle α. A movable plate that rotates with the rotating shaft is installed on the rotating shaft of the stepper motor. One end of the horizontal fixed plate corresponds to the end of the movable plate installed on the rotating shaft as the vertex. Starting from the overlapping position of the fixed plate and the movable plate, the movable plate rotates to form an angle between the fixed plate and the movable plate. The pad with an inclination angle α is made by adjusting the angle between the fixed plate and the movable plate, ensuring that the shape of the pad matches the inclination angle α of the coating, and maintaining the flatness and parallelism of the pad.
6. The method for preparing a sample for full-thickness structure display of a coating according to claim 1, characterized in that: In step (4), during the sample embedding process, a pad with an inclination angle α is placed at the bottom of the mold cavity, and the coating surface of the sample is facing downward and close to the pad with an inclination angle α; during the grinding and polishing process, sandpaper is first used for grinding, and then a polishing machine is used for polishing, so that the full thickness structure of the coating is clearly visible.