Coating and matrix binding force detection sample and test method

Abstract

The invention provides a test sample and a test method for detecting the binding force of a coating and a matrix, the test sample comprises a handle part and a test sample body which are connected with each other and a coating attached to the surface of the test sample body, and the axes of the handle part and the test sample body are on the same straight line; the sample body is provided with at least one pair of symmetrical planes in the radial direction, an edge is formed at the intersection of two adjacent planes, and the wedge angle of the normal section of the edge is the same as the wedge angle of the normal section of a cutter cutting edge; the test method comprises the following steps: grinding the sample and the cutter together, carrying out coating pretreatment on the sample and the cutter together, coating the sample and the cutter together, and finally carrying out indentation or scratch detection on the plane of the sample body. According to the test sample and the test method for detecting the binding force of the coating and the matrix, the structure of the test sample and the test method for detecting the binding force of the test sample are improved, so that the test result of the binding force of the test sample more accurately represents the binding force condition of a cutter.

Description

Technical Field

[0001] This invention relates to the field of coating performance testing technology, and more specifically, to a sample and testing method for testing the adhesion between a coating and a substrate. Background Technology

[0002] Coated cutting tools improve wear resistance, thermal shock resistance, and chemical stability by depositing one or more layers of hard material on their surface, thereby extending tool life and reducing production costs. Coated cutting tools are widely used in modern manufacturing. During the research and development and manufacturing of coated cutting tools, the performance of the coating needs to be tested. However, for tools with complex structures, such as solid carbide tools, some indicators are difficult to test directly due to their complex surface structure. To better evaluate the coating performance, test specimens are often used to test relevant properties. Among these, the adhesion between the coating and the substrate is one of the important factors affecting tool performance; the closer the specimen structure is to the tool, the more accurately it can characterize the adhesion. On the other hand, correct and appropriate testing methods are also crucial for ensuring testing accuracy.

[0003] For example, patent application number 202211665276.2, entitled "Method for Testing Coating Bond Strength and Sample Brushing Apparatus," describes a method for testing coating bond strength that includes: driving a wheel-type brush to rotate around the axis of the brush shaft, and using the rotating wheel-type brush to brush the coated area of ​​the sample; obtaining the wear condition of the sample, and determining the coating bond strength based on the wear condition. While brushing tests are often used for preliminary assessment of coating wear resistance, their results often fail to accurately reflect the wear resistance performance of the coating in actual cutting applications. Brushing tests are only suitable for preliminary screening or quality control of coatings. This patent application also only provides a testing method and does not provide precise design and monitoring of the sample structure and sample manufacturing process to enable the sample to more accurately characterize the adhesion of the tool coating.

[0004] The invention patent application with application number 202310150241.3, entitled "Test Specimen and Test Method for Tool Coating Performance," describes a technical solution where the specimen can be applied to various tests, and multiple tests can be performed on the same specimen, thereby reducing the number of specimens required in tool research, thus saving testing costs and improving testing efficiency. The patent designs the specimen structure, which includes a specimen substrate and a specimen coating covering the surface of the substrate. The specimen surface includes an outer peripheral surface, a first plane, and a second plane. The outer peripheral surface and the second plane intersect to form corners, which are used for brushing tests. The first plane is used for scratch or indentation tests, with the corners simulating the cutting edge. However, this patent still has the following problems: 1. When performing scratch or indentation tests on the first plane, both scratch and indentation tests require leveling, necessitating a positioning surface parallel to the test surface to accurately measure the scratches and indentations on the test surface. The sample 101 in this patent is cylindrical at one end and arc-shaped at the other end, which has a first plane and a second plane. This structure is difficult to level, which may lead to deviations in the critical load values ​​of indentations or scratches, thus affecting the accurate assessment of coating adhesion. 2. This patent also uses a brush grinding test to measure the coating adhesion strength at the cutting edge of the tool. Similar to the above, the brush grinding test cannot truly reflect the wear resistance of the coating in actual cutting applications.

[0005] In summary, existing technologies have made efforts to improve the test results of the test specimens to more accurately characterize the bonding force between the tool substrate and the coating. However, there are still technical problems that the test specimen structure and test methods cannot accurately characterize the bonding force between the tool substrate and the coating. Summary of the Invention

[0006] The technical problem to be solved by this invention is that, in the existing technology for testing the bonding force of cutting tools using samples, the sample structure and testing method still cannot accurately characterize the bonding force between the tool substrate and the coating. This invention provides a sample and testing method that can more accurately reflect the bonding force between the tool coating and the substrate.

[0007] A coating-substrate adhesion testing specimen includes a shank and a specimen body connected to each other. The specimen body includes a substrate and a coating attached to the surface of the substrate. The axes of the shank and the specimen body are collinear. The specimen body has at least one pair of symmetrical planes in the radial direction, wherein the intersection of two adjacent planes forms an edge, the edge being equivalent to the cutting edge of the simulated tool, and the two sides of the edge being equivalent to the rake face and flank face of the simulated tool, respectively. The wedge angle of the edge profile is the same as the wedge angle of the cutting edge profile.

[0008] The angle between the rake face and the flank face is a wedge angle.

[0009] When the cutting tool is a solid carbide end mill, the solid carbide end mill includes a split end edge and a side edge. The cutting edge mentioned in this invention refers to the side edge of the solid carbide end mill. Solid carbide end mills, with their complex structures and intricate profiles, make it difficult to find a suitable plane for measurement during indentation and scratch testing, thus hindering the accurate acquisition of coating adhesion test data. Therefore, test samples are used for testing.

[0010] Furthermore, a straight groove is formed on one of the planes, the length direction of the straight groove being parallel to the axis of the sample body; the straight groove is located near one edge of the plane containing the straight groove, and the straight groove intersects with the adjacent face to form the edge; the face of the straight groove near the edge is equivalent to the rake face of the simulated tool, the adjacent face is equivalent to the flank face of the simulated tool, and the wedge angle of the edge method section is the same as the wedge angle of the tool cutting edge method section.

[0011] The sample described in this invention has the same matrix material, grinding process, and pre-coating treatment process as the simulated cutting tool. The same equipment and process are used for grinding, pre-coating treatment, and coating of the sample and the cutting tool. In order to more accurately characterize the adhesion of the coating on the cutting tool, the sample described in this invention is also designed with the same shank as the cutting tool for clamping, so as to ensure that the sample and the cutting tool have the same processing conditions.

[0012] The specimen has at least one pair of symmetrical planes to facilitate clamping and positioning during scratch or indentation tests. Furthermore, a straight groove similar to the cross-section of a tool's chip breaker is provided on one of the planes, along with an edge equivalent to the cutting edge structure. The side of the straight groove near the edge is equivalent to the rake face of the simulated tool, and the adjacent surface near the edge of the plane with the straight groove is equivalent to the flank face of the simulated tool. The included angle between the rake face and flank face near the edge of the straight groove is equal to the wedge angle of the tool's cutting edge profile. The specimen structure of this invention can simulate the shank, rake face, flank face, chip breaker, cutting edge, and wedge angle of a tool. The structure is simple, closely approximating the tool's structure, and facilitates scratch and indentation tests, providing a more accurate characterization of the tool's coating adhesion. It is suitable for testing the coating adhesion of hard, complex solid carbide end mills.

[0013] Furthermore, the handle is cylindrical, and the sample body has four faces in the radial direction.

[0014] Furthermore, the four faces of the sample are face one, face two, face three, and face four, with face one and face three being symmetrical, and face two and face four being symmetrical. The straight groove is on face one and is close to face two, with the intersection of the straight groove and face two forming the edge. In this case, the side of the straight groove near the edge is equivalent to the rake face of the simulated tool, and face two is equivalent to the flank face of the simulated tool.

[0015] Furthermore, the four faces of the sample are face one, face two, face three, and face four, with face one and face three being symmetrical, and face two and face four being symmetrical. The straight groove is opened on face one and is close to face four, with the intersection of the straight groove and face four being the edge. In this case, the side of the straight groove near the edge is equivalent to the rake face of the simulated tool, and face four is equivalent to the flank face of the simulated tool.

[0016] Furthermore, all four sides of the sample are planes.

[0017] Furthermore, surfaces one and three are planes, while surfaces two and four are curved surfaces.

[0018] Furthermore, the outer diameter of the circumscribed circle of the sample is less than or equal to the diameter of the handle.

[0019] This invention also provides a testing method for testing the adhesion between the coating and the substrate of a cutting tool using the coating-substrate adhesion test sample described above, specifically including the following steps: S1: Grind the sample and the tool together. After grinding, observe the difference between the edge and the cutting edge of the tool to ensure that the sample surface and the tool surface have the same surface integrity. S2: Perform pre-coating treatment on the sample and the tool together. After the pre-coating treatment is completed, measure the passivation value of the sample edges to monitor the effect of the pre-coating treatment process and ensure that the pre-coating treatment of the sample and the tool are of the same degree. S3: Coat the sample and the cutting tool together; S4: Coating adhesion test: Indentation or scratch test is performed on the surface of the sample. By measuring the critical load of the indentation or scratch, the adhesion of the tool coating is equivalently evaluated.

[0020] In this invention, observing the differences between the edge and the cutting edge of the tool refers to observing the differences between the edge and the cutting edge of the tool, such as the serrations and notches.

[0021] This invention first ensures that the sample and the cutting tool are manufactured using the same methods, including: 1. Designing the sample structure to facilitate indentation and scratch testing while closely resembling the tool body, thus improving testing accuracy. 2. Performing the same grinding process on both the sample and the cutting tool, observing whether the serrations and notches on the edges are the same as those on the cutting edge, ensuring that the edges of the sample and the cutting edge have the same surface integrity. 3. Performing the same pre-coating treatment on both the sample and the cutting tool, measuring the edge passivation value of the sample, ensuring that the pre-coating treatment effect of the sample is the same as that of the cutting tool. 4. Coating both the sample and the cutting tool together. These four points ensure that the manufacturing methods, grinding, and pre-coating treatment effects of the sample and the cutting tool are the same, guaranteeing that the subsequent indentation and scratch test results of the sample closely resemble the actual cutting tool, thus ensuring the accuracy of the coating adhesion strength test. For example, in step S1, if the sample surface has obvious unevenness or scratches, or serrations and notches, it may cause deviations in the critical load measurement values ​​of the indentation or scratch, thereby affecting the accurate assessment of the coating adhesion strength. Therefore, during the sample preparation process, the surface of the sample must be strictly inspected to ensure that it has the same quality as the tool surface.

[0022] It should also be noted that the sample is designed with a shank, which can be clamped in the equipment like a cutting tool during grinding, pre-coating and coating processes, ensuring that the sample and the cutting tool have the same working conditions during grinding, pre-coating and coating processes.

[0023] The pretreatment processes in this invention typically include surface roughness control and passivation. Studies have shown that appropriate pretreatment can significantly reduce defects in the tool manufacturing process and form the desired surface microstructure, thereby improving coating adhesion and tool cutting performance.

[0024] Critical load is an important indicator for evaluating the adhesion of tool coatings, and its measurement process requires comprehensive analysis in conjunction with the results of indentation or scratch testing. Specifically, critical load refers to the minimum load value corresponding to the occurrence of peeling or cracking of the coating in indentation or scratch testing, and its magnitude is directly proportional to the bonding strength between the coating and the substrate.

[0025] Further, in step S1, the serrations and notches of the edge are observed with an electron microscope to distinguish them from the cutting edge of the tool; in step S2, the passivation value of the edge of the sample is measured with a three-dimensional profile measuring instrument.

[0026] The present invention has the following beneficial effects: The coating-substrate adhesion testing specimen and method described in this invention improve upon both the specimen structure and the testing method for specimen adhesion, enabling the test results to more accurately characterize the adhesion of the cutting tool. The specimen structure is improved as follows: 1. A shank is designed so that the specimen, like the cutting tool, can be clamped in the processing equipment for grinding, pre-coating treatment, and coating treatment under the same conditions; 2. The specimen body has at least one pair of symmetrical planes, facilitating leveling during indentation or scratch testing; 3. The angle between the face near the edge of the straight groove and its adjacent face is equal to the wedge angle of the cutting edge section of the cutting tool, used to simulate the wedge angle of the cutting tool; 4. A straight groove is designed on the plane, similar in cross-sectional shape to the chip breaker groove of the cutting tool. The designs in points 3 and 4 above make the specimen structure closer to the cutting tool, allowing the test results to more accurately characterize the adhesion of the cutting tool.

[0027] Improvements to the testing method: 1. Perform the same grinding treatment as the cutting tool and observe whether the grinding effect is the same as that of the cutting tool; 2. Perform the same pre-coating treatment as the cutting tool and observe whether the effect of the pre-coating process is the same as that of the cutting tool; 3. Coat the sample and the cutting tool together. These three points ensure that the sample manufacturing method is the same as the cutting tool manufacturing method, and that the edge grinding effect and edge passivation value are the same as those of the cutting tool, allowing the testing of the coating adhesion of the sample to more accurately characterize the adhesion of the cutting tool. Attached Figure Description

[0028] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a three-dimensional view of the coating-substrate adhesion test sample from Example 1; Figure 2 This is a cross-sectional view of the coating-substrate adhesion test sample from Example 1; Figure 3 This is a front view of the sample used for testing the adhesion between the coating and the substrate in Example 2; Figure 4 This is a cross-sectional view of the sample used for testing the adhesion between the coating and the substrate in Example 2; Figure 5 This is a three-dimensional view of the coating-substrate adhesion test sample from Example 3; Figure 6 This is a cross-sectional view of the sample used for testing the adhesion between the coating and the substrate in Example 3; Figure 7 This is a three-dimensional view of the coating-substrate adhesion test sample from Example 4; Figure 8 This is a cross-sectional view of the sample used for testing the adhesion between the coating and the substrate in Example 4; Figure 9 This is a cross-sectional view of the coating-substrate adhesion test sample from Example 5.

[0029] The serial numbers are: 1-handle, 2-sample body, 3-face one, 4-face two, 5-face three, 6-face four, 7-edge, 8-straight groove. Detailed Implementation

[0030] Example 1 A test specimen for assessing the adhesion between a coating and a substrate, such as Figure 1 As shown, the sample includes a handle 1 and a sample body 2 connected to each other. The sample body 2 is a cuboid with four planes. The sample body 2 includes a substrate and a coating attached to the surface of the substrate. The axes of the handle 1 and the sample body 2 are on the same straight line. The sample body 2 has at least one pair of symmetrical planes in the radial direction. In this embodiment, the sample body 2 is a cuboid with a square cross-section and two pairs of symmetrical planes. The intersection of two adjacent faces forms an edge, and the included angle α between the two faces is equal to the wedge angle of the cutting edge profile of the tool. The handle 1 is cylindrical, as shown... Figure 2 As shown, the diameter of the handle 1 is equal to the circumscribed circle diameter of the sample body 2.

[0031] The four faces of the sample 2 are face 3, face 4, face 5, and face 6. Face 3 and face 5 are symmetrical, face 4 and face 6 are symmetrical, and faces 3, 4, 5, and 6 are all complete planes. Figure 1 Face 3 is equivalent to the rake face of the simulated tool, face 4 is equivalent to the flank face of the simulated tool, the edge at the intersection of face 3 and face 4 is equivalent to the cutting edge of the tool, and the included angle α between face 3 and face 4 is equivalent to the wedge angle of the tool's cutting edge profile. This embodiment improves the sample structure, making it convenient for indentation and scratch testing, and making the sample structure closer to the tool structure, allowing the test results of the sample's adhesion force to more accurately characterize the adhesion of the tool's coating. 1. The shank 1 is designed so that the sample, like the tool, can be clamped in the processing equipment for grinding, pre-coating treatment, and coating treatment under the same conditions; 2. The sample body 2 has two pairs of symmetrical planes, facilitating leveling during indentation and scratch testing; 3. The included angle between the plane and its adjacent face is equal to the wedge angle of the tool's cutting edge profile.

[0032] Example 2 A test specimen for assessing the adhesion between a coating and a substrate, such as Figure 3 and Figure 4 As shown, the difference between Example 2 and Example 1 is that the cross-section of the sample body 2 is rectangular.

[0033] Example 3 A test specimen for assessing the adhesion between a coating and a substrate, such as Figure 5 and Figure 6 As shown, the difference between Example 3 and Example 2 is that the sample body 2 includes a pair of symmetrical planes and a pair of symmetrical curved surfaces, as shown in the figure. Figure 5 As shown, surface 3 is a plane, surface 4 is a curved surface, surface 3 is equivalent to the rake face of the simulated tool, surface 4 is equivalent to the flank face of the simulated tool, the edge at the intersection of surface 3 and surface 4 is equivalent to the cutting edge of the simulated tool, and the included angle α between surface 3 and surface 4 is equivalent to the wedge angle of the cutting edge profile of the tool.

[0034] Example 4 A coating-substrate adhesion test specimen, differing from Example 1, has a straight groove 8 formed on surface 3, as shown. Figure 7 As shown, the length direction of the straight groove 8 is parallel to the axis of the sample body 2, and the cross-section of the straight groove 8 is similar in shape to the cross-section of the tool chip breaker groove, such as... Figure 8 The cross-section of the sample is shown, revealing the cross-section of the straight groove 8; the straight groove 8 is located near the edge of the plane containing the straight groove 8 (i.e., the edge L of surface 3, as shown). Figure 7 As shown, the straight groove 8 is located on surface 3 (close to edge L), and the straight groove 8 intersects with surface 4 to form edge 7. The wedge angle of the normal section of edge 7 is the same as the wedge angle of the normal section of the cutting edge of the tool. The included angle α between the side surface (side surface a) of the straight groove 8 close to edge 7 and surface 4 is equal to the wedge angle of the tool.

[0035] In this embodiment, the straight groove 8 is set to be equivalent to the chip breaking groove of the tool, so that the structure of the sample is closer to the tool. By adjusting the structure of the straight groove, the wedge angle of the edge is better equal to the wedge angle of the tool being tested. When performing indentation or scratch testing, the test result of the adhesion can more accurately characterize the adhesion of the tool coating.

[0036] Example 5 A coating-substrate adhesion test specimen, which differs from Example 4 in that, as... Figure 9 As shown, the straight groove 8 is opened on surface 3 and is close to surface 6. The intersection of the straight groove 8 and surface 6 is the edge 7. The angle α between the side of the straight groove 8 close to the edge 7 and surface 6 is equal to the wedge angle of the tool.

[0037] Example 6 A testing method for testing the coating-substrate adhesion strength of a cutting tool using a coating-substrate adhesion test sample as described in any one of Examples 1 to 5, specifically includes the following steps: S1: Grind the sample and the tool together. After grinding, observe the difference between the serrations and notches of the edge 7 and the cutting edge of the tool to ensure that the sample surface and the tool surface have the same surface integrity. S2: Perform pre-coating treatment on the sample and the tool together. After the pre-coating treatment is completed, measure the passivation value of the edge 7 of the sample to monitor the effect of the pre-coating treatment process and ensure that the pre-coating treatment of the sample and the tool are of the same degree. S3: Coat the sample and the cutting tool together; S4: Coating adhesion test: Indentation or scratch test is performed on the surface of the sample. By measuring the critical load of the indentation or scratch, the adhesion of the tool coating is equivalently evaluated.

[0038] In step S1, the serrations and notches of the edge 7 are observed with an electron microscope to compare with the cutting edge of the tool; in step S2, the passivation value of the edge 7 of the sample is measured with a three-dimensional profile measuring instrument.

[0039] The test method described in this embodiment, combined with the coating-substrate adhesion test specimen described in any one of Embodiments 1 to 5, makes the test results of the specimen adhesion more accurately characterize the adhesion of the tool.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the present invention.

Claims

1. A test specimen for testing the adhesion between a coating and a substrate, characterized in that, The sample includes an interconnected shank and a sample body, the sample body comprising a substrate and a coating attached to the surface of the substrate; the axes of the shank and the sample body are collinear; the sample body has at least one pair of symmetrical planes in the radial direction, wherein the intersection of two adjacent planes forms an edge, the edge being equivalent to the cutting edge of the simulated tool, and the faces on both sides of the edge being equivalent to the rake face and flank face of the simulated tool, respectively; the wedge angle of the edge profile is the same as the wedge angle of the cutting edge profile.

2. The coating-substrate adhesion test specimen according to claim 1, characterized in that, One of the planes has a straight groove, the length of which is parallel to the axis of the specimen. The straight groove is close to one edge of the plane where it is located, and the straight groove intersects with the adjacent plane to form the edge. The plane of the straight groove close to the edge is equivalent to the rake face of the simulated tool, and the adjacent plane is equivalent to the flank face of the simulated tool. The wedge angle of the edge section is the same as the wedge angle of the tool cutting edge section.

3. The coating-substrate adhesion test specimen according to claim 2, characterized in that, The handle is cylindrical, and the sample body has four faces in the radial direction.

4. The coating-substrate adhesion test specimen according to claim 3, characterized in that, The four faces of the sample are face one, face two, face three and face four. Face one and face three are symmetrical, and face two and face four are symmetrical. The straight groove is opened on face one and is close to face two. The intersection of the straight groove and face two is the edge.

5. The coating-substrate adhesion test specimen according to claim 3, characterized in that, The four faces of the sample are face one, face two, face three and face four. Face one and face three are symmetrical, and face two and face four are symmetrical. The straight groove is opened on face one and is close to face four. The intersection of the straight groove and face four is the edge.

6. The coating-substrate adhesion test specimen according to claim 4 or 5, characterized in that, All four sides of the sample are planes.

7. The coating-substrate adhesion test specimen according to claim 4 or 5, characterized in that, Surface 1 and Surface 3 are planes, while surface 2 and Surface 4 are curved surfaces.

8. The coating-substrate adhesion test specimen according to claim 3, characterized in that, The diameter of the outer circumscribed circle of the specimen is less than or equal to the diameter of the handle.

9. A testing method, characterized in that, The coating-substrate adhesion test specimen according to any one of claims 1-8 is used to test the adhesion between the coating and the substrate of the cutting tool, specifically including the following steps: S1: Grind the sample and the tool together. After grinding, observe the difference between the edge and the cutting edge of the tool to ensure that the sample surface and the tool surface have the same surface integrity. S2: Perform pre-coating treatment on the sample and the tool together. After the pre-coating treatment is completed, measure the passivation value of the sample edges to monitor the effect of the pre-coating treatment process and ensure that the pre-coating treatment of the sample and the tool are of the same degree. S3: Coat the sample and the cutting tool together; S4: Coating adhesion test: Indentation or scratch test is performed on the surface of the sample. By measuring the critical load of the indentation or scratch, the adhesion of the tool coating is equivalently evaluated.

10. The test method according to claim 9, characterized in that, In step S1, the differences between the edge and the cutting edge of the tool are observed using an electron microscope; in step S2, the passivation value of the edge of the sample is measured using a three-dimensional profile measuring instrument.

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