Equipment and method for testing bonding strength of coating in high-temperature environment

Abstract

The invention discloses equipment and a method for testing the bonding strength of a coating in a high-temperature environment, and belongs to the field of material performance testing. Comprising a mechanical loading system, a high-temperature furnace body, a coating clamp and a to-be-tested sample, the to-be-tested sample comprises a coating and a base body, a clamp groove consistent with the coating in thickness is formed in the side face of the coating clamp, and the side, provided with the coating, of the to-be-tested sample is clamped in the clamp groove to form a crisscross sample; an upper pressing rod and a supporting device which are connected with the mechanical loading system respectively extend into the high-temperature furnace body from the top wall and the bottom wall; a supporting seat provided with a sample groove is arranged at the top of the supporting device, a coating clamp of a cross sample is vertically placed in the sample groove, and a sample to be tested is transversely arranged on one side of the top surface of the sample groove; the upper pressing rod is located above the coating clamp, and an interval with the set height is formed between the bottom end of the coating clamp and the bottom face of the sample groove. According to the invention, accurate testing of the bonding strength of the coating in a high-temperature environment is realized. And the equipment is simple, efficient and high in reliability.

Description

Technical Field

[0001] The present invention relates to the field of material performance testing, and in particular to a coating bonding strength testing device and a testing method under a high temperature environment. Background Art

[0002] For coated materials that are used in high temperature environments, the bonding strength between the coating and the substrate directly determines its reliability and safety. When evaluating the bonding strength of the coating interface, traditional methods such as the pull-out method, the shear method, and the scratch method have their own applications, but they all have certain limitations.

[0003] In the national standard "Test Method for Interface Strength of Fine Ceramics - Cross Loading Method" (GB / T 31541-2015), a test method is described, which involves bonding two pieces of fine ceramic materials with an adhesive to form a cross-shaped specimen. Subsequently, a load is applied with the aid of a matching fixture to induce shear and tensile stress states at the bonding interface. Through this process, the precise measurement and evaluation of the shear strength and tensile strength of the fine ceramic interface is achieved.

[0004] Nevertheless, the cross-cross method still has some inherent limitations. First, in the shear strength test, the shear surface is not subjected to pure shear stress, which may lead to deviations in the test results. Secondly, this standard is applicable to testing the tensile and shear strength of the adhesive interface, and is not applicable to testing the bonding strength of coating materials. Then, when testing the bonding strength of the coating interface, the cross-cross method is also limited by potential factors such as the strength of the adhesive itself. The adhesive is easy to soften and fail at high temperatures, and it cannot effectively bond with the coating, and it is impossible to complete the accurate test of the coating bonding strength. Summary of the invention

[0005] The present invention provides a coating bonding strength testing device and a testing method under high temperature environment, which realizes accurate testing of coating bonding strength under high temperature environment. The device is simple, efficient and highly reliable.

[0006] The present invention provides the following technical solutions:

[0007] A coating bonding strength testing device under high temperature environment comprises a mechanical loading system, a high temperature furnace, a coating fixture and a sample to be tested, wherein:

[0008] The main body of the test sample and the coating fixture is a rectangular parallelepiped structure, the test sample includes a coating and a substrate, and the coating is arranged on one side of the substrate; a fixture groove is opened on the side of the coating fixture, and the thickness of the fixture groove is consistent with the thickness of the coating;

[0009] The coating fixture is arranged vertically, the sample to be tested is arranged horizontally, and the side of the sample to be tested having the coating is clamped in the fixture groove, so that the sample to be tested and the coating fixture form a cross sample; the coating is provided with vertical coating grooves at two vertical edges of the fixture groove for disconnecting the coating;

[0010] The top wall and the bottom wall of the high-temperature furnace body are provided with through holes, and a heating element is provided in the high-temperature furnace body; the upper and lower parts of the mechanical loading system are respectively connected with an upper pressure rod and a supporting device, and the upper pressure rod and the supporting device extend into the high-temperature furnace body from the through holes on the top wall and the bottom wall of the high-temperature furnace body respectively;

[0011] A support seat is provided at the top of the support device, a sample groove is provided on the support seat, the coating fixture of the cross sample is vertically placed in the sample groove, and the sample to be tested of the cross sample is horizontally arranged on one side of the top surface of the sample groove;

[0012] The upper pressing rod is located above the coating fixture, and a gap of a set height is formed between the bottom end of the coating fixture and the bottom surface of the sample groove.

[0013] Furthermore, the support device is connected to a driving device for driving the support device to rotate along the vertical axis, the number of the sample grooves is multiple, and the multiple sample grooves are evenly arranged on the support seat with the vertical axis as the center at set angle intervals, and a cross sample is set in each sample groove;

[0014] The supporting device is driven to rotate by the driving device, and the coating fixtures of the cross-shaped samples are rotated to the position directly below the upper pressing rod in sequence.

[0015] Furthermore, the support seat includes a base and a plurality of fixtures, each fixture having a sample groove on its top surface, and a plurality of slots on its top surface. The plurality of slots are evenly arranged at set angles on the support seat with the vertical axis as the center, and a fixture is detachably installed in each slot.

[0016] Furthermore, a connecting groove is provided on the bottom surface of the base, and a connecting protrusion is provided on the top of the supporting device, and the connecting protrusion is cooperatively connected with the connecting groove.

[0017] Furthermore, the driving device includes a motor, which is arranged outside the high-temperature furnace body and connected to the supporting device through a transmission device.

[0018] Furthermore, the contact portion between the bottom of the supporting device and the mechanical loading system and the contact portion between the upper pressure rod and the mechanical loading system are connected to a water cooling system.

[0019] Furthermore, the mechanical loading system is connected to a mechanical loading control system, and the high-temperature furnace is connected to a temperature control system.

[0020] Furthermore, the heating element is a silicon-molybdenum rod, and the coating fixture is made of silicon carbide or heat-resistant ceramics.

[0021] Furthermore, the transmission device includes a gear-like structure and a transmission belt, the gear-like structure is arranged on the supporting device, and the motor is connected to the gear-like structure through the transmission belt.

[0022] A method for testing a coating bonding strength test device under a high temperature environment, the method comprising:

[0023] S1: preparing a sample to be tested with the coating groove, and placing the sample to be tested horizontally, placing the coating fixture vertically, and clamping the side of the sample to be tested with the coating in the fixture groove, so that the sample to be tested and the coating fixture form a cross sample;

[0024] Wherein, the two coating grooves of the sample to be tested are located at the two vertical edges of the fixture groove;

[0025] S2: A cross specimen is placed in each specimen groove, and one of the cross-shaped coating fixtures is placed directly below the upper pressure rod;

[0026] Wherein, the coating fixture of the cross sample is vertically placed in the sample groove, and the sample to be tested of the cross sample is horizontally arranged on one side of the top surface of the sample groove;

[0027] S3: closing the door of the high-temperature furnace body, heating the high-temperature furnace body by the heating element; after the temperature of the high-temperature furnace body rises to the set temperature, keeping the temperature for the set time;

[0028] S4: The upper pressure rod is driven by the mechanical loading system to load a cross sample directly below to test the coating interface bonding strength. After the test is completed, the upper pressure rod returns to the initial position;

[0029] S5: Turn on the driving device to drive the supporting device to rotate, so that the next cross sample rotates to the bottom of the upper pressure rod, and return to S4 until all cross samples are tested;

[0030] S6: Enter the cooling stage until the high-temperature furnace body cools down to room temperature, open the furnace door, and take out the cross-section specimen after the test.

[0031] The present invention has the following beneficial effects:

[0032] The present invention improves the cross-cross specimen by providing a fixture groove with the same thickness as the coating on the coating fixture. After forming a cross-cross specimen with the test sample, the bonding surface of the coating and the substrate is aligned with the side of the coating fixture. When loading, the pressure acts on the bonding surface of the coating and the substrate, so that the bonding surface is subjected to pure shear stress, thereby improving the accuracy of the coating bonding strength test results. In addition, the cross-cross specimen of the present invention does not use an adhesive, and there will be no problem of adhesive softening and failure at high temperatures, thereby achieving accurate testing of the coating bonding strength under high temperature environments. The equipment is simple, efficient, and highly reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a schematic diagram of a coating bonding strength testing device under a high temperature environment of the present invention;

[0034] FIG2 is a schematic diagram of a coating fixture;

[0035] FIG3 is a schematic diagram of a sample to be tested;

[0036] FIG4 is a schematic diagram of a cross specimen formed by a coating fixture and a sample to be tested;

[0037] FIG5 is a schematic diagram of placing a cross sample on a fixture;

[0038] FIG6 is a schematic diagram of a combination of a fixture and a cross-shaped specimen;

[0039] FIG7 is a top view of the base of the support seat;

[0040] FIG8 is a side view of the base of the support seat;

[0041] FIG9 is a top view of the support base;

[0042] FIG10 is a side view of the support base;

[0043] FIG11 is a schematic diagram of a supporting device;

[0044] FIG. 12 is a schematic diagram of the support device and the support base after being combined. DETAILED DESCRIPTION

[0045] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0046] An embodiment of the present invention provides a coating bonding strength testing device under high temperature environment, as shown in FIGS. 1-12 , comprising a mechanical loading system 1, a high temperature furnace body 2, a coating fixture 14 and a sample to be tested 19, wherein:

[0047] The main body of the test sample 19 and the coating fixture 14 is a rectangular parallelepiped structure. The test sample 19 includes a coating 15 and a substrate 17, and the coating 15 is arranged on one side of the substrate 17. The coating fixture 14 is made of silicon carbide or heat-resistant ceramics, and a fixture groove 21 is provided on its side for clamping the test sample 19. The thickness of the fixture groove 21 is consistent with the thickness of the coating 15.

[0048] The coating fixture 14 is arranged vertically, and the sample to be tested 19 is arranged horizontally. The side of the sample to be tested 19 with the coating 15 is stuck in the fixture groove 21, so that the sample to be tested 19 and the coating fixture 14 form a cross sample 6. The coating 15 is provided with vertical coating grooves 16 at the two vertical edges of the fixture groove 21 to disconnect the coating 15. The coatings in the two coating grooves 16 participate in the test, and the coatings in other areas do not participate in the test, so that the effective length of the coating participating in the test is consistent with the size of the fixture groove 21, thereby improving the test accuracy.

[0049] Through holes are provided on the top wall and the bottom wall of the high temperature furnace body 2, and a heating element 3 is provided in the high temperature furnace body 2. The heating element 3 can be a silicon molybdenum rod, and the maximum test temperature reaches 1600°C, which can realize accurate testing of the bonding strength of the coating within the temperature range of 1600°C. The high temperature furnace body 2 is connected to a temperature control system 9, and the temperature of the high temperature furnace body 2 is controlled by the temperature control system 9.

[0050] The mechanical loading system 1 is connected to the mechanical loading control system 11, and the loading of the mechanical loading system 1 is controlled by the mechanical loading control system 11. The upper and lower parts of the mechanical loading system 1 are respectively connected with an upper pressure rod 7 and a supporting device 8, and the upper pressure rod 7 and the supporting device 8 extend into the high-temperature furnace body 2 from the through holes on the top wall and the bottom wall of the high-temperature furnace body 2 respectively. The upper pressure rod 7 is a rod-shaped structure, and the supporting device 8 is a columnar structure.

[0051] A support seat 23 is provided on the top of the support device 8 , and a sample groove 24 is opened on the support seat 23 . The coating fixture 14 of the cross sample 6 is vertically placed in the sample groove 24 , and the test sample 19 of the cross sample 6 is horizontally arranged on one side of the top surface of the sample groove 24 .

[0052] The upper pressure rod 7 is located directly above the coating fixture 14. The bottom end of the coating fixture 14 and the bottom surface of the sample groove 24 are spaced at a set height so as to have a deformation space when pressure is applied.

[0053] When the existing cross-cross method is used to test the tensile and shear strength of the adhesive interface, the horizontal and vertical components are bonded together with a certain thickness of adhesive to form a cross-cross specimen. When loading, due to the certain thickness of the adhesive, the shear surface is not subjected to pure shear stress, but also to a portion of bending moment, which leads to deviations in the test results.

[0054] The present invention improves the cross-cross test specimen. By setting a fixture groove with the same thickness as the coating on the coating fixture, after forming a cross-cross test specimen with the test specimen, the bonding surface of the coating and the substrate is aligned with the side of the coating fixture. When loading, the pressure acts on the bonding surface of the coating and the substrate, so that the bonding surface is subjected to pure shear stress, thereby improving the accuracy of the coating bonding strength test result. In addition, the cross-cross test specimen of the present invention does not use an adhesive, and there will be no problem of adhesive softening and failure at high temperatures, thereby achieving accurate testing of the coating bonding strength under high temperature environments.

[0055] From the above, it can be seen that the present invention realizes the accurate measurement of the bonding strength of the coating in a high temperature environment, and the equipment is simple, efficient and reliable.

[0056] Traditional coating bonding strength testing in high temperature environments can only test a single sample at a time, and has many problems such as long cycle, low efficiency and high energy consumption.

[0057] To solve the above problems, the support device 8 of the present invention is connected to a driving device 12 that drives the support device 8 to rotate 360° along the vertical axis. The number of the aforementioned sample grooves 24 is multiple, and the multiple sample grooves 24 are evenly arranged at set angle intervals with the vertical axis as the center of the circle on the support seat 23, and a cross sample 6 is set in each sample groove 24. For example, the number of sample grooves 24 is 6, and the center lines thereof are evenly distributed at 60° angle intervals.

[0058] The supporting device 8 is driven by the driving device 12 to freely rotate 360°, so that the coating fixtures 14 of multiple cross samples 6 are rotated to the bottom of the upper pressure rod 7 in sequence, and each cross sample 6 is tested in sequence.

[0059] The present invention can carry multiple samples during a high-temperature test by setting a rotating device, thereby improving the test efficiency many times.

[0060] The present invention does not limit the specific form of the driving device 12. In one example, the driving device 12 includes a motor, which is arranged outside the high-temperature furnace body 2 and connected to the supporting device 8 through a transmission device.

[0061] Specifically, the transmission device includes a gear-like structure 26 and a transmission belt 13. The gear-like structure 26 is arranged on the lower part of the support device 8. The motor is connected to the gear-like structure 26 through the transmission belt 13 to drive the support device 8 to rotate 360 ​​degrees.

[0062] Of course, the transmission device may also be in other forms, and the present invention is not limited thereto. For example, it may also be a transmission device such as a gearbox.

[0063] The motor can be set to rotate once to drive the support device to rotate a set angle each time, so that the next cross sample is rotated just below the upper pressure rod 7. For example, when the number of sample grooves 24 is 6, the motor drives the support device to rotate 60° at a time.

[0064] The present invention does not limit the specific structural form of the support seat 23. In one example, the support seat 23 can be a simple block structure, and a plurality of sample grooves 24 can be directly opened on the top surface of the block structure.

[0065] In another example, the support seat 23 includes a base 4 and a plurality of fixtures 5, each fixture 5 having a sample groove 24 on the top surface, and a plurality of slots 20 on the top surface of the support seat 23. The plurality of slots 20 are evenly arranged at set angles on the support seat 23 with the vertical axis as the center, and a fixture 5 is detachably installed in each slot 20.

[0066] When in use, the cross sample 6 is first placed in the sample groove 24 of the fixture 5 , and then the assembly 18 of the fixture 5 and the cross sample 6 is placed in the slot 20 on the support seat 23 .

[0067] A connecting groove 22 is provided on the bottom surface of the base 4, and a connecting protrusion 25 is provided on the top of the supporting device 8. The connecting protrusion 25 cooperates with the connecting groove 22 to realize a detachable connection between the supporting device 8 and the base 4 of the supporting seat 23. The base 4 can rotate freely driven by the supporting device 8.

[0068] The contact part 27 (which is the base of the support device 8) between the bottom of the support device 8 and the mechanical loading system 1, and the contact part 28 between the upper pressure rod 7 and the mechanical loading system 1 are connected to the water cooling system 10. Under the action of the water cooling system 10, the upper pressure rod 7 and the support device 8 are prevented from overheating, thereby preventing the mechanical test system 1 from being damaged or malfunctioning.

[0069] Specifically, cooling pipes may be provided in the contact parts 27 and 28, and the cooling pipes are connected to the water cooling system 10 to achieve temperature reduction and cooling.

[0070] The embodiment of the present invention further provides a method for testing the coating bonding strength testing device under the aforementioned high temperature environment, the method comprising:

[0071] S1: Prepare a test sample 19 with a coating groove 16, and place the test sample 19 horizontally, and place the coating fixture 14 vertically, and clamp the side of the test sample 19 with the coating 15 in the fixture groove 21, so that the test sample 19 and the coating fixture 14 form a cross sample 6.

[0072] It is necessary to make the two coating grooves 16 of the sample 19 to be tested be located at the two vertical edges of the fixture groove 21 .

[0073] S2: A cross sample 6 is placed in each sample groove 24 , and one of the cross-shaped coating fixtures 14 is placed directly below the upper pressure rod 7 .

[0074] The coating fixture 14 of the cross sample 6 is vertically placed in the sample groove 24 , and the sample to be tested 19 of the cross sample 6 is horizontally arranged on one side of the top surface of the sample groove 24 .

[0075] When the support seat 23 includes a base 4 and a plurality of fixtures 5, the cross sample 6 is first placed in the middle position of the sample groove 24 of the fixture 5 to form a combination 18 of the cross sample 6 and the fixture 5, and then the combination 18 is placed in the slot 20 on the support seat 23, and multiple ones are placed in turn.

[0076] S3: Close the door of the high-temperature furnace body 2, and heat the high-temperature furnace body 2 through the heating element 3. After the temperature of the high-temperature furnace body 2 rises to the set temperature, keep it warm for a set time (for example, 5 minutes).

[0077] Specifically, a temperature rising program may be set through the temperature control system 9 to perform heating.

[0078] When there is a water cooling system 10 , the water cooling system 10 needs to be turned on at the same time.

[0079] S4: The upper pressure rod 7 is driven by the mechanical loading system 1 to load a cross sample 6 directly below to test the coating interface bonding strength. After the test is completed, the upper pressure rod 7 returns to the initial position.

[0080] S5: Turn on the driving device 12, drive the supporting device 8 to rotate, rotate the next cross sample 6 to the bottom of the upper pressure rod 7, return to S4, test the next cross sample 6, and repeat in sequence until all cross samples are tested.

[0081] S6: After all cross-section specimens are tested, enter the cooling stage until the high-temperature furnace body 2 cools to room temperature, open the furnace door, and take out the cross-section specimens after the test. Finally, close the furnace door, turn off the water cooling system, and the coating interface strength test operation is completed.

[0082] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A coating bonding strength testing device under high temperature environment, characterized in that: It includes a mechanical loading system, a high temperature furnace, a coating fixture and a sample to be tested, including: The main body of the test sample and the coating fixture is a rectangular parallelepiped structure, the test sample includes a coating and a substrate, and the coating is arranged on one side of the substrate; a fixture groove is opened on the side of the coating fixture, and the thickness of the fixture groove is consistent with the thickness of the coating; The coating fixture is arranged vertically, the sample to be tested is arranged horizontally, and the side of the sample to be tested having the coating is clamped in the fixture groove, so that the sample to be tested and the coating fixture form a cross sample; the coating is provided with vertical coating grooves at two vertical edges of the fixture groove for disconnecting the coating; The top wall and the bottom wall of the high-temperature furnace body are provided with through holes, and a heating element is provided in the high-temperature furnace body; the upper and lower parts of the mechanical loading system are respectively connected with an upper pressure rod and a supporting device, and the upper pressure rod and the supporting device extend into the high-temperature furnace body from the through holes on the top wall and the bottom wall of the high-temperature furnace body respectively; A support seat is provided at the top of the support device, a sample groove is provided on the support seat, the coating fixture of the cross sample is vertically placed in the sample groove, and the sample to be tested of the cross sample is horizontally arranged on one side of the top surface of the sample groove; The upper pressing rod is located above the coating fixture, and a gap of a set height is formed between the bottom end of the coating fixture and the bottom surface of the sample groove.

2. The coating bonding strength testing equipment under high temperature environment according to claim 1, characterized in that: The support device is connected to a driving device for driving the support device to rotate along a vertical axis. The number of the sample grooves is multiple, and the multiple sample grooves are evenly arranged on the support seat at set angle intervals with the vertical axis as the center, and a cross sample is set in each sample groove; The supporting device is driven to rotate by the driving device, and the coating fixtures of the cross-shaped samples are rotated to the position directly below the upper pressing rod in sequence.

3. The coating bonding strength testing equipment under high temperature environment according to claim 2, characterized in that: The support seat includes a base and multiple clamps, each clamp is provided with a sample groove on the top surface, and multiple clamping slots are provided on the top surface of the support seat. The multiple clamping slots are evenly arranged on the support seat at set angles with the vertical axis as the center, and a clamp is detachably installed in each clamping slot.

4. The coating bonding strength testing equipment under high temperature environment according to claim 3, characterized in that: A connecting groove is formed on the bottom surface of the base, and a connecting protrusion is formed on the top of the supporting device, and the connecting protrusion is matched and connected with the connecting groove.

5. The coating bonding strength testing equipment under high temperature environment according to claim 4, characterized in that: The driving device comprises a motor, which is arranged outside the high-temperature furnace body and connected to the supporting device via a transmission device.

6. The coating bonding strength testing equipment under high temperature environment according to claim 5, characterized in that: The contact portion between the bottom of the support device and the mechanical loading system and the contact portion between the upper pressure rod and the mechanical loading system are connected to a water cooling system.

7. The coating bonding strength testing equipment under high temperature environment according to claim 6, characterized in that: The mechanical loading system is connected to a mechanical loading control system, and the high-temperature furnace body is connected to a temperature control system.

8. The coating bonding strength testing equipment under high temperature environment according to claim 7, characterized in that: The heating element is a silicon-molybdenum rod, and the coating fixture is made of silicon carbide or heat-resistant ceramics.

9. The coating bonding strength testing equipment under high temperature environment according to claim 8, characterized in that: The transmission device comprises a gear-like structure and a transmission belt. The gear-like structure is arranged on the supporting device, and the motor is connected to the gear-like structure through the transmission belt.

10. A method for testing a coating bonding strength test device under a high temperature environment as claimed in any one of claims 2 to 9, characterized in that: The method comprises: S1: preparing a sample to be tested with the coating groove, and placing the sample to be tested horizontally, placing the coating fixture vertically, and clamping the side of the sample to be tested with the coating in the fixture groove, so that the sample to be tested and the coating fixture form a cross sample; Wherein, the two coating grooves of the sample to be tested are located at the two vertical edges of the fixture groove; S2: A cross specimen is placed in each specimen groove, and one of the cross-shaped coating fixtures is placed directly below the upper pressure rod; Wherein, the coating fixture of the cross sample is vertically placed in the sample groove, and the sample to be tested of the cross sample is horizontally arranged on one side of the top surface of the sample groove; S3: closing the door of the high-temperature furnace body, heating the high-temperature furnace body by the heating element; after the temperature of the high-temperature furnace body rises to the set temperature, keeping the temperature for the set time; S4: The upper pressure rod is driven by the mechanical loading system to load a cross sample directly below to test the coating interface bonding strength. After the test is completed, the upper pressure rod returns to the initial position; S5: Turn on the driving device to drive the supporting device to rotate, so that the next cross sample rotates to the bottom of the upper pressure rod, and return to S4 until all cross samples are tested; S6: Enter the cooling stage until the high-temperature furnace body cools down to room temperature, open the furnace door, and take out the cross-section specimen after the test.

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