Bond strength testing apparatus and method for hard coated composite materials

Abstract

The application provides a method for testing the bonding strength of a hard coating composite material, comprising the steps of: first, using a laser to heat the hard coating on the surface of the hard coating composite material to form a laser heating area; then, moving a stylus of a scratch tester along the laser heating area to form a scratch line on the hard coating; the laser heating area comprises a heating apex and a heating center line, the heating apex is the contact point between the stylus and the hard coating, and the heating center line is aligned with the extension line of the scratch line and intersects with the heating apex. The above method can simulate the environment that causes wear to the hard coating during the testing process, so that the bonding strength testing environment of the hard coating composite material is closer to the actual working environment, thereby improving the accuracy of the bonding strength testing data and better reflecting the anti-peeling performance of the hard coating composite material in actual use. The application also provides a device for testing the bonding strength of a hard coating composite material.

Description

Technical Field

[0001] This invention relates to the field of superhard material performance testing, specifically to a device and method for testing the bonding strength of hard coated composite materials. Background Technology

[0002] Machine tool cutting tools include polycrystalline diamond, polycrystalline cubic boron nitride, ceramic tools, cemented carbide, high-speed steel, etc. To improve machining accuracy and extend tool life, hard coatings such as TiN, TiC, and Al2O3 are applied to the tool surface. These hard coatings have high bonding strength to the tool surface and do not easily peel off, thus providing long-term protection for the tool. Therefore, the bonding strength is an important performance parameter of the hard coating.

[0003] In existing technologies, the scratch test is commonly used to measure the bonding strength of hard coatings. The testing equipment is a scratch tester, which uses a scratch tester to scratch the coating and record the load at the location where the coating peels off. The scratch tester's scratch tester is placed perpendicular to the coating plane, and its movement direction is parallel to the coating plane and perpendicular to the coating's cross-section (side surface), that is, it applies force to the coating in a direction perpendicular to the coating's cross-section.

[0004] However, cutting tools are used in complex scenarios, especially in precision machining, which often involves high-speed and high-temperature conditions. For example, polycrystalline cubic boron nitride (PCBN) cutting tools can reach cutting speeds of up to 1000 m / min and tool temperatures of around 1000℃. The peeling of the hard coating on the tool surface is not affected by a single force or factor, but by multiple forces and actions. A single scratch force can only roughly reflect the hard coating's resistance to peeling caused by abrasive wear, and cannot fully and accurately reflect the hard coating's resistance to peeling during actual use. Therefore, using existing scratch testers to measure the adhesion strength of tool coatings is usually inaccurate. In actual use, tools with weaker adhesion may even experience coating peeling more easily than those with weaker adhesion. Summary of the Invention

[0005] In view of this, it is necessary for the present invention to provide a device and method for testing the bonding strength of hard coated composite materials in order to overcome the above-mentioned problems.

[0006] Hard-coated composite materials used in cutting tools often encounter complex operating environments, including high-speed and high-temperature conditions. This leads to the peeling of the hard coating on the tool surface due to various wear mechanisms. Specifically, these mechanisms include abrasive wear caused by impurities in the workpiece, adhesive wear due to high temperatures, elemental diffusion wear, and chemical wear. Therefore, this invention provides a method for testing the bonding strength of hard-coated composite materials. This method incorporates multiple modes of action on the hard coating during the measurement process, allowing for a more accurate assessment of the peeling resistance of the hard coating on the tool surface during actual use, thereby improving the accuracy of the bonding strength test.

[0007] Specifically, the technical solution of the bonding strength test method for hard-coated composite materials provided by the present invention includes: firstly, using a laser to heat the hard coating on the surface of the hard-coated composite material to form a laser heating zone; then, the laser heating zone moves with the scratching needle of the scratching instrument, and the scratching needle forms a scratch line on the hard coating; wherein, the laser heating zone includes a heating vertex and a heating center line, the heating vertex is the contact point between the scratching needle and the hard coating, and the heating center line is aligned with the extension line of the scratch line and intersects at the heating vertex.

[0008] In this text, "heating vertex" refers to the vertex of the laser heating zone, and "heating center line" refers to the center line of the laser heating zone.

[0009] Based on the above, the shape of the laser heating zone is either fan-shaped or triangular.

[0010] Based on the above, in the laser heating zone, the temperature of the heating vertex is the highest point, and the temperature gradually decreases as it moves away from the heating vertex.

[0011] The temperature distribution within the laser heating zone is uneven, and the temperature of the heating peak, which is the highest temperature point, is preferably 800-1300℃, more preferably 800℃, 900℃, 1000℃, 1100℃, 1200℃, 1300℃, etc.

[0012] Based on the above, the method for forming the laser-heated zone includes heating the hard coating at the heating apex using multiple laser beams. The temperature distribution of the laser-heated zone formed by the multiple laser beams is the same as the temperature distribution in actual applications of the hard coating composite material, and the multiple laser beams include a first laser beam generated by a first laser that irradiates the front side of the coating and a second laser beam generated by a second laser that irradiates the side surface.

[0013] The heating vertex is the most critical heating location affecting the detachment of the hard coating. It significantly influences not only stress-induced detachment but also subsequent detachment due to elemental diffusion and chemical reactions. The heating vertex is not only the hottest point in the laser heating zone but also the point where the interaction between the scribing needle and the hard coating is most intense. For example, when the hard coating composite material is used as a cutting tool in actual workpiece cutting, this point is where chemical reactions and thermal diffusion are most intense. Therefore, multiple lasers are used to generate multiple laser beams to optimize the heating of the heating vertex.

[0014] Based on the above, the method for forming the laser heating zone includes: irradiating the upper surface of the hard coating with at least one first laser beam substantially perpendicularly, and irradiating the side surface of the hard coating with at least two second laser beams perpendicularly, wherein the heating apex is located at the heating center of the first and second laser beams. When there are multiple first laser beams, these multiple first laser beams are arranged in parallel to form a fan-shaped or triangular apex heating zone with the highest temperature at the scratch point, gradually decreasing in temperature towards the rear. Using multiple first laser beams can accurately simulate the temperature distribution of various actual tool working environments. The laser spot can be circular with a diameter of 30–400 nm.

[0015] Based on the above, the step of forming the laser heating zone includes: firstly depositing a diffusion element layer on the hard coating, and then heating the diffusion element layer to diffuse the elements therein into the hard coating. The diffusion element layer contains elements that can diffuse from the workpiece to the cutting tool during actual cutting; preferably, the diffusion element layer contains metallic elements such as iron, carbon, nickel, and chromium.

[0016] When hard-coated composite materials are used as cutting tools, the hard coating is subjected to continuous and prolonged friction from the workpiece cutting surface (flank face) or chips (rake face) during actual cutting. This process causes element diffusion into the hard coating. Scratch testers only scratch the hard coating momentarily and cannot accurately simulate the element diffusion process. This invention involves depositing a diffusion element layer on the surface of the hard coating and heating this layer to pre-infiltrate the hard coating with the diffusion elements. This heating process is completed during the sample preparation stage, i.e., before the scratch test begins.

[0017] Based on the above, after the step of depositing the diffusion element layer and before heating the diffusion element layer, the method further includes the step of depositing a TiO2 layer on the surface of the diffusion element layer to prevent the element from diffusing into the external environment and to allow the diffusion element to diffuse into the hard coating. In order not to affect the accuracy of the test of the adhesion of the hard coating, the thickness of the TiO2 layer does not exceed 100 nm.

[0018] Based on the above, the steps for forming the scratch line include: first providing a chemical reaction gas to the heating vertex, and then forming the scratch line on the hard coating; wherein, the chemical reaction gas is a gas that can chemically react with the hard coating composite material during actual use.

[0019] Based on the above, the chemical reaction gas includes oxygen-containing gas, carbon-containing gas, or a mixture of both. Preferably, the oxygen-containing gas is O3. O3 has a stronger oxidizing power than O2 in the environment during the actual workpiece cutting process. However, during the actual workpiece cutting process, the hard coating has a long time to react with oxygen. Therefore, using the highly oxidizing O3 can compensate for the short reaction time during the scratch test. The carbon gas can be methane, ethane, acetylene, or other gases.

[0020] The present invention also provides a bonding strength testing device for hard coated composite materials, including a sample stage, a scratch tester, a laser emitting device, a chemical environment introduction device, and a slide rail assembly;

[0021] The sample stage can be used to place the sample to be tested, and the sample to be tested is a hard-coated composite material with a hard coating formed on its surface.

[0022] The scratching device includes a scratching needle that traverses the hard coating in a straight line to form a scratch line;

[0023] The laser emitting device includes a first laser and a second laser. The first laser generates at least one first laser beam that is substantially perpendicular to the upper surface of the hard coating, while the second laser generates at least two second laser beams that are perpendicular to the side surface of the hard coating, for forming a laser heating area. The scribing needle is located at the heating apex of the laser heating area.

[0024] The chemical environment introduction device includes a chemical reaction gas supply structure, a gas pipeline and a nozzle. The two ends of the gas pipeline are respectively connected to the chemical reaction gas supply structure and the nozzle. The nozzle is used to spray chemical reaction gas into the point where the hard coating and the scriber contact.

[0025] The slide rail assembly includes a slide rail and a base mounted on the slide rail, on which the first laser, the second laser, and the nozzle are mounted, such that the first laser, the second laser, and the nozzle move synchronously with the scribe needle on the slide rail.

[0026] Preferably, the slide rail and the scriber each have an independent but synchronized drive mechanism.

[0027] Therefore, the bonding strength test method for hard-coated composite materials provided by the present invention introduces various environments that can cause wear to the hard coating, such as thermal environment, element diffusion and chemical reaction, during the measurement process. This makes the bonding strength test environment of the hard-coated composite material closer to its actual working environment, thereby improving the accuracy of the bonding strength test data and better reflecting the anti-peeling performance of the hard-coated composite material in actual use.

[0028] The bonding strength testing device for hard-coated composite materials provided by this invention uses a scratch tester as the main measuring device. Based on the scratch tester, a laser emission device for introducing a thermal environment and a chemical environment introduction device are added to increase the influence of thermal and chemical environments on scratch measurement, thereby improving the accuracy of the testing device in detecting the bonding strength of hard coatings. Attached Figure Description

[0029] Figure 1 This is a front view of the bonding strength testing device for hard coated composite materials provided in Embodiment 1 of the present invention. The sample stage and the sample to be tested are not shown in this figure.

[0030] Figure 2 yes Figure 1 The side view of the bonding strength testing device shown.

[0031] Figure 3 This is a top view of the scratches formed during use by the bonding strength testing device provided in Embodiment 1 of the present invention.

[0032] Figure 4 This is a schematic diagram of the formation of the fan-shaped laser heating zone in the bonding strength test method for hard coated composite materials provided in Embodiment 3 of the present invention.

[0033] The component symbols in each figure are as follows: 10 Sample stage, 11 Sample to be tested, 12 Scribing needle, 14 Scribing line, 20 First laser beam, 21 First support structure, 22 Second laser beam, 23 Second support structure, 24 Laser heating zone, 25 Heating vertex, 30 Chemical reaction gas supply structure, 31 Gas pipeline, 32 Nozzle, 33 Third support structure, 40 Slide rail assembly, 41 Slide rail, 42 Slider, 43 Base. Detailed Implementation

[0034] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0035] Example 1

[0036] Please see Figures 1 to 3 This embodiment provides a bonding strength testing device for hard coated composite materials, including a sample stage 10, a scratch tester, a laser emitting device, a chemical environment introduction device, and a slide rail assembly 40.

[0037] The sample stage 10 is used to statically place the sample 11 to be tested, and the sample to be tested is a hard-coated composite material with a hard coating formed on its surface. In this embodiment, the sample stage 10 is an existing structure and is a detection platform used by an existing scratch tester.

[0038] The scratch tester is an existing instrument used to measure the adhesion strength of hard coatings; it includes a scratch needle 12 and a scratch driving mechanism that drives the scratch needle 12. Under the action of its driving mechanism, the scratch needle 12 scratches the hard coating in a straight line and forms a scratch line 14.

[0039] The laser emitting device includes a first laser and a second laser, used to form a laser heating zone 24 at the contact point between the hard coating surface and the scratching instrument. The first and second lasers have essentially the same structure as existing lasers, with the main difference being that the first laser generates at least one first laser beam 20 that is substantially perpendicular to the upper surface of the hard coating, while the second laser generates at least two second laser beams that are perpendicular to the side surface of the hard coating, forming the laser heating zone 24. This laser heating zone 24 contacts the scratching needle 12 at the heating vertex 25, placing the scratching needle 12 at the heating vertex 25 of the laser heating zone 24, meaning the scratch line 14 is located at the rear end of the laser heating area 23. In this embodiment, the first laser generates one first laser beam 20, and the second laser generates two second laser beams; the light spots of these three laser beams form a triangular laser heating zone 24 on the hard coating. In other embodiments, the first laser is a plurality of parallel first laser beams 20, forming multiple laser spots on the top surface of the hard coating, thereby forming a fan-shaped laser heating zone with the spots formed by the second laser beam generated by the second laser, where the temperature decreases and expands backward from the scratch point. The first laser is fixed to the slide rail assembly 40 by a first support structure 21, and the second laser is fixed to the slide rail assembly 40 by a second support structure 23.

[0040] The chemical environment introduction device is used to introduce a gas that can chemically react with the hard coating during actual use of the cutting tool onto the hard coating surface. The chemical environment introduction device includes a chemical reaction gas supply structure 30, a gas pipeline 31, and a nozzle 32. The two ends of the gas pipeline 31 are connected to the chemical reaction gas supply structure 30 and the nozzle 32, respectively. The nozzle 32 is used to spray the chemical reaction gas onto the heated vertex 25 where the hard coating and the scribing needle 12 contact. The nozzle 32 is fixed to the slide rail assembly 40 by a third support structure 33. The chemical environment introduction device includes multiple chemical reaction gas supply structures 30. Each chemical reaction gas supply structure 30 is an oxygen source gas supply structure, a carbon source gas supply structure, or a combination of both. The oxygen source gas supply structure is an ozone generator. The carbon source gas supply structure is a carbon source gas cylinder. In this embodiment, the chemical reaction gas supply structure 30 consists of an ozone generator and a methane cylinder.

[0041] The slide rail assembly 40 includes a slide rail 41, a slider 42 mounted on the slide rail 41, a base 43 fixed on the slider 42, and a slide rail drive mechanism for driving the slide rail 41. In this embodiment, the slide rail 41 is a lead screw slide rail. The slider 42, driven by its drive mechanism, can carry the base 43 and move freely on the slide rail 41. The movement trajectory of the slider 42 is parallel to the movement trajectory of the scriber 12, and the slide rail 41 and the scriber 12 move synchronously. The first laser, the second laser, and the nozzle 32 are respectively fixed on the base 43 by the first support structure 21, the second support structure 23, and the third support structure 33, so that the first laser, the second laser, and the nozzle 32 move on the slide rail 41, and this movement is synchronized with the movement of the scriber 42, thereby making the laser heating zone 24 movable, moving with the scriber 12, and providing chemical reaction gas to the heating vertex 25 through the nozzle 32, and the scriber 12 forming a scratch line 14 on the hard coating.

[0042] Example 2

[0043] This embodiment provides a method for testing the bonding strength of a hard-coated composite material, wherein the hard-coated composite material will be used as a cutting tool. The bonding strength testing method includes the following steps:

[0044] First, multiple laser beams are used to heat the hard coating on the surface of the hard coating composite material to form a laser heating zone; wherein, the laser heating zone includes a heating vertex and a heating center line, wherein the heating vertex is the vertex of the laser heating zone, and the heating center line is the center line of the laser heating zone;

[0045] Then the laser heating area advances with the scratching needle of the scratching instrument, and the scratching needle forms a scratch line on the hard coating; wherein, the heating vertex is the contact point between the scratching needle and the hard coating, the heating center line and the extension line of the scratch line of the scratching needle are strictly aligned and intersect at the heating vertex, that is, the laser heating area is located in the area not reached by the scratching needle in the direction of the scratching needle's advance.

[0046] This embodiment can use the bonding strength testing device for hard-coated composite materials provided in Embodiment 1 to detect the bonding strength of the hard coating. Specifically, in the step of forming the laser heating zone, the hard-coated composite material sample to be tested is statically fixed on the sample stage 10, and a first laser beam 20 generated by a first laser and two second laser beams generated by a second laser are used to form a fan-shaped laser heating zone 24, as shown below. Figure 3 As shown, the laser heating zone 24 can essentially simulate the temperature distribution on the surface of the cutting tool during actual use. The first laser beam 20 is irradiated substantially perpendicularly onto the upper surface of the hard coating where the heating vertex 25 is located. A small portion of the laser spot, less than 10% of the spot area, falls on the scribing needle 12 to ensure that there is no heating blank area in the hard coating section to be scribed in front of the scribing needle 12. The second laser irradiates the side surface of the plane where the hard coating is located, that is, the fresh cut surface of the hard coating. In this embodiment, the spots of the first laser beam 21 and the second laser are both circular, with a diameter of 120–240 nm.

[0047] The temperature value of the laser heating zone 24 is not uniformly distributed throughout the entire sector area, with the highest temperature at the heating apex. The temperature range is 800 to 1300°C, and the specific temperature is determined based on the actual temperature of the hard-coated composite material used as a cutting tool during cutting.

[0048] The slider 42 in the slide rail assembly 40 drives the first laser and the second laser on the base 43 to move along the slide rail 41, so that the laser heating area 24 moves forward synchronously with the scribing needle 12, and the scribing needle 12 forms a scratch line 14 on the hard coating. Then, the scribing instrument is used to detect the bonding strength of the hard coating.

[0049] Specifically, the temperature decreases along the scratch line 14 in a direction away from the heating vertex 25. The slope of the temperature decrease (cooling rate) is determined based on the actual cutting of the workpiece by the hard-coated composite material as a cutting tool. For example, the temperature decreases rapidly, for example, when the scratch line is 3 to 10 mm long, there is a temperature difference of not less than 300°C, preferably not less than 400°C, within 2 mm, to simulate the effect of thermal shock on the peeling of the hard coating.

[0050] Example 3

[0051] Please see Figure 4This embodiment provides a method for testing the bonding strength of a hard-coated composite material. This bonding strength testing method is basically the same as the one provided in Embodiment 2, with the main difference being: In this embodiment, the first laser generates multiple parallel first laser beams 20 oriented vertically downwards. These multiple parallel first laser beams 20 vertically irradiate the top surface of the hard coating, generating multiple light spots. Simultaneously, together with the second laser beam 22 generated by the second laser, they form a fan-shaped laser heating zone 24 on the hard coating, where the temperature decreases and expands backwards from the scratch point. Because the first laser generates multiple first laser beams 20, the temperature distribution pattern on the surface of the hard-coated composite material tool can be adjusted with greater freedom, more accurately simulating the temperature field during actual tool use. This is because the temperature field on the surface of the hard-coated composite material tool is significantly different under different cutting conditions; for example, even when cutting the same workpiece, the temperature field varies considerably under different feed rates and linear velocities.

[0052] Example 4

[0053] This embodiment provides a method for testing the bonding strength of a hard-coated composite material. This method is essentially the same as the method provided in Embodiments 2 or 3, with the main difference being that the sample to be tested is pretreated before forming the laser heating zone. Specifically, before forming the laser heating zone on the hard-coated composite material using laser heating, a diffusion element layer is first deposited on the surface of the hard coating, and then a titanium oxide (TiO2) layer with a thickness not exceeding 100 nm is deposited on the top surface of the diffusion element layer.

[0054] The diffusion element layer contains elements that can diffuse from the workpiece to the cutting tool during the actual cutting process, such as metallic elements like iron, carbon, nickel, and chromium.

[0055] The TiO2 layer is used to prevent diffusing elements from escaping outwards during heating rather than diffusing into the hard coating. It also acts as an anti-reflective layer during subsequent scratching processes when laser irradiation heats the coating. The TiO2 layer can exert compressive stress on the hard coating, simulating the pressure exerted on the hard coating by the workpiece cutting surface (flank face) or chips (rake face) during cutting. TiO2 possesses suitable hardness, transparency, and chemical stability, and exhibits good physicochemical property matching with hard coatings such as titanium nitride, titanium aluminum nitride, and alumina, making it an excellent anti-diffusion layer. While silicon oxide and silicon nitride also offer good anti-diffusion properties, their physicochemical property matching with hard coatings is inferior to that of TiO2, and therefore they are not used. TiO2 with appropriate thickness and stress can accurately simulate the effect of element diffusion on coating adhesion without compromising measurement accuracy.

[0056] Example 5

[0057] This embodiment provides a method for testing the bonding strength of a hard-coated composite material. This bonding strength testing method is basically the same as the method provided in Embodiments 2, 3, or 4, with the main difference being: first, a chemical reaction gas is provided to the heating vertex, and then the scratch line is formed on the hard coating. Specifically, during the scratch test, sufficient O3, methane, or other gases that will chemically react with the hard coating during the actual workpiece cutting process are provided to the point where the scratch is just made, that is, the point where the scribe line contacts the hard coating.

[0058] Test data

[0059] Samples: Five batches of cubic boron nitride cutting tools coated with TiN layers are provided. In actual production, the performance of cubic boron nitride cutting tools coated with TiN layers in the same batch is basically the same.

[0060] Test method: 1) The metal column specimens of the above 5 batches of samples were cut to process them into bearing steel. The TiN coating in the contact area between the back face of the tool and the metal specimen was completely removed as the standard. The number of workpieces completed was recorded as shown in Table 1.

[0061] 2) The bonding strength of the above 5 batches of samples was measured using the traditional method, that is, the bonding strength of the samples was directly measured using only a scratch tester. The results are shown in Table 1.

[0062] 3) The bonding strength of the above five batches of samples was measured using the method provided in Embodiment 5 of the present invention. Before the test, an iron diffusion layer was first deposited on the surface of the tool, and then a TiO2 layer was deposited on the iron diffusion layer before the test was performed. Moreover, ozone and methane were introduced into the scratch area on the surface of the tool during the test, and the first laser generated only one first laser beam.

[0063] Table 1. Statistics on Bond Strength and Number of Workpieces Processed

[0064]

[0065] As can be seen from Table 1, traditional methods for measuring bonding strength cannot reveal significant differences in tool bonding strength, resulting in poor consistency with the actual number of workpieces processed. The measurement method provided in this embodiment of the invention can better measure the differences in tool bonding strength, with a high degree of consistency with the number of workpieces processed.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for testing the bonding strength of a hard coating composite material, comprising the steps of: depositing a diffusion element layer on the hard coating; heating the diffusion element layer to diffuse elements in the diffusion element layer into the hard coating; heating the hard coating into which the elements are diffused by laser to form a laser heating zone; and moving a stylus of a scratch tester along the laser heating zone to form a scratch line on the hard coating into which the elements are diffused. The laser heating area comprises a heating vertex and a heating center line, the heating vertex being a contact point of the scribe needle and the element-diffused hard coating, and the heating center line being aligned with an extension line of the scribe line and intersecting at the heating vertex; The step of forming the scribe line comprises: providing a chemical reaction gas to the heating vertex first, and then forming the scribe line on the element-diffused hard coating; wherein the chemical reaction gas is a gas that can chemically react with the element-diffused hard coating in actual use of the element-diffused hard coating composite material.

2. The method of testing the bonding strength according to claim 1, wherein The laser heating area is in the shape of a fan or a triangle.

3. The method of testing the bonding strength according to claim 2, wherein In the laser heating area, the temperature of the heating vertex is the highest, and gradually decreases in a direction away from the heating vertex.

4. The method of testing the bonding strength according to claim 3, wherein The method of forming the laser heating area comprises heating the hard coating at the heating vertex by using a plurality of laser beams.

5. The method of testing the bonding strength according to claim 4, wherein The method of forming the laser heating area comprises: using at least one first laser beam to irradiate substantially perpendicularly on the upper surface of the hard coating, using at least two second laser beams to irradiate perpendicularly on the side surface of the hard coating, and the heating vertex being located at the heating center of the first laser beam and the second laser beam.

6. The method of testing the bond strength according to any one of claims 1 to 5, characterized in that, After the step of depositing the diffusion element layer and before the step of heating the diffusion element layer, a step of depositing a TiO2 layer on the surface of the diffusion element layer is further included, the thickness of the TiO2 layer being not more than 100 nm.

7. The method of testing the bonding strength according to any one of claims 1 to 5, characterized in that, The chemical reaction gas comprises an oxygen-containing gas, a carbon-containing gas, or a mixture of the two.

8. A device for testing the bonding strength of a hard coated composite material, characterized by The apparatus comprises a sample stage, a scribe instrument, a laser emitting device, a chemical environment introducing device, and a slide rail assembly; The sample stage is used to statically place a hard coating composite material to be tested thereon, and a hard coating is formed on the surface of the hard coating composite material to be tested; The scribe instrument comprises a scribe needle, which linearly forms a scribe line on the hard coating; The laser emitting device comprises a first laser and a second laser, the first laser is used to generate at least one first laser beam to irradiate substantially perpendicularly on the upper surface of the hard coating, and the second laser is used to generate at least two second laser beams to irradiate perpendicularly on the side surface of the hard coating, thereby forming a laser heating area; the scribe needle is located at a heating vertex of the laser heating area; The chemical environment introducing device comprises a chemical reaction gas supply structure, a gas pipeline, and a nozzle, two ends of the gas pipeline are respectively connected to the chemical reaction gas supply structure and the nozzle, and the nozzle is used to spray the chemical reaction gas to a point where the hard coating and the scribe needle contact; The slide rail assembly comprises a slide rail and a base mounted on the slide rail, the first laser, the second laser, and the nozzle are mounted on the base, so that the first laser, the second laser, and the nozzle move synchronously with the scribe needle on the slide rail; The method for testing the bonding strength of the hard coating composite material by using a bonding strength testing device is the bonding strength testing method according to any one of claims 1 to 7.

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