Diamond microindentation probe and microindentation testing equipment

Abstract

This disclosure discloses a diamond microindentation probe and a microindentation testing device, comprising a quartz glass mounting rod forming a quartz glass base. The quartz glass base has a mounting hole into which a diamond indenter is installed. The bottom of the diamond indenter is configured as a micron-sized needle tip. When using the microindentation testing device proposed in this disclosure to perform micron-level indentation testing, the interference of micron-scale defects during thin film preparation on the macroscopic mechanical properties of the material can be eliminated. The mechanical properties of the material itself, such as the elastic modulus, as well as other thermomechanical properties and fatigue performance, can be calculated.

Description

Technical Field

[0001] This disclosure relates to the field of indentation testing equipment at the micrometer scale, and more particularly to a diamond micrometer indentation probe and micrometer indentation testing equipment. Background Technology

[0002] A thermomechanical analyzer (TMA) is a precision instrument used to study the thermal expansion, phase transition, stress relaxation, and other properties of materials under programmed temperature control. Its basic principle is to analyze the thermomechanical properties of materials by measuring the deformation of a sample under varying temperature conditions while applying a load. TMAs are widely used in plastics, rubber, ceramics, metals, composite materials, electronic materials, new energy, and biomedical materials. In the plastics and rubber industry, TMAs can be used to determine parameters such as the coefficient of thermal expansion and glass transition temperature; in the ceramics and building materials field, they can assess the thermal stability of materials; in metal and alloy research, TMAs can observe deformation behavior during heating or cooling; in composite materials and electronic materials, they can test interlayer properties and the warpage of encapsulation materials; and in new energy and biomedical materials, TMAs are used to study the thermomechanical properties of lithium-ion battery materials, fuel cell catalysts, and more.

[0003] Thermomechanical analyzers (TMAs) employ a variety of probe designs. They support multiple measurement modes, including linear expansion mode (measuring the coefficient of thermal expansion), puncture mode (testing hardness), compression mode (studying compressive deformation), and tensile mode (observing tensile properties). Through these modes, TMAs provide crucial data support for materials design, process optimization, and engineering applications. Puncture probes, typically employing a protruding needle probe, apply force to a small area of ​​the sample to measure its softening point and melting behavior, making them particularly suitable for coating measurements. The probe material is usually quartz, which possesses a low coefficient of thermal expansion and high temperature resistance, ensuring measurement accuracy under high-temperature conditions.

[0004] It should be noted that in existing technologies, puncture probes are generally made of quartz glass, which has limited hardness. Furthermore, the design of existing puncture probes is generally quite simple; for example, common puncture probes are directly ground from the tip of a quartz glass rod, resulting in low processing precision, failing to reach the dimensional accuracy of tens of micrometers. Limitations in probe shape and construction may affect the accuracy and stability of punctures. Differences in processing precision between different probes lead to low repeatability of results, making quantitative calculations impossible. In addition, some probes may not be suitable for samples with varying hardness and elasticity, resulting in inaccurate measurement results. Therefore, the scope of testing capabilities for existing puncture probes is limited, generally used for the composition and structural analysis of multilayer thin films or simple testing of the Tg of coating materials.

[0005] Nanoindentation, also known as depth-sensing indentation (DSI), is a method for testing the mechanical properties of materials. Its principle involves using a computer-controlled indenter to press into the material surface, recording changes in load and indentation depth in real time to obtain a load-depth curve. By analyzing this curve, mechanical properties such as hardness, elastic modulus, and fracture toughness can be calculated. This technique offers high spatial resolution and is particularly suitable for testing the mechanical properties of ultrathin materials such as films and coatings, measuring parameters such as hardness, elastic modulus, creep behavior, and viscoelasticity. Nanoindentation is widely used in materials science and engineering, including films and coatings, micro / nanomaterials, composite materials, and biomaterials. Furthermore, it is combined with atomic force microscopy (AFM) for in-situ measurements, further expanding its application scope. The advantages of nanoindentation lie in its high precision and wide applicability, providing crucial data support for materials design, performance optimization, and engineering applications.

[0006] For composite films, nanoindentation is an excellent testing technique that can test the hardness, elastic modulus, creep behavior, viscoelasticity, and even analyze the interfacial mechanical behavior of composite films. However, the technique is complex to operate and has high equipment and maintenance costs, which limits its application in enterprise product development.

[0007] For composite films, macroscopic hardness testing is insufficient to reflect the material's mechanical properties. Furthermore, film thicknesses are typically less than 100 μm, requiring stacking to a certain thickness for hardness testing. Macroscopic tensile property tests prepare centimeter-scale samples. The performance of polymer films is influenced by the fabrication process and microscopic film-forming defects; therefore, macroscopic tensile properties are often related to, but not entirely identical to, the material's inherent properties. Consequently, during product development, careful differentiation is often needed to determine whether mechanical properties reflect the composite material itself or the film fabrication process. Summary of the Invention

[0008] In view of the shortcomings of the prior art, this disclosure aims to at least solve one of the technical problems existing in the prior art or related technologies.

[0009] Therefore, this disclosure proposes a diamond microindentation probe and a microindentation testing device, which can reflect the mechanical characteristics and thermomechanical properties of the material itself during testing.

[0010] For composite thin films, compared with macroscopic mechanical testing methods (such as tensile testing, bending testing, and compression testing), the micrometer-level indentation testing technology using the micrometer indentation testing equipment proposed in this disclosure can eliminate the interference of micrometer-scale defects in the thin film preparation process on the macroscopic mechanical properties of the material, and calculate the mechanical properties of the material itself, such as elastic modulus, as well as other thermomechanical properties, fatigue performance, etc.

[0011] First, the diamond micron indentation probe disclosed herein includes a quartz glass mounting rod, which forms a quartz glass base. The quartz glass base has a mounting hole, in which a diamond indenter is installed. The bottom of the diamond indenter is configured as a micron-sized needle tip.

[0012] In one possible implementation, the diamond indenter is bonded or embedded in a mounting hole, and the needle tip protrudes from the bottom of the quartz glass base.

[0013] In one feasible implementation, the surface roughness of the needle tip within 150 micrometers from the tip to the root needs to be less than 50 nm, and the depth to which the needle tip is pressed into the object to be tested is 1-130 μm.

[0014] In one feasible implementation, the needle tip is configured as a Vickers tip or a cubic angle tip, with an effective tip height of not less than 150 micrometers.

[0015] In one feasible implementation, the cubic angle needle tip is required to have the following: (1) the included angle of the pyramidal surface is 65°18'±30', and the included angle of the line is 77°3'±30'; (2) the difference in the inclination angle of the diamond indenter's central axis relative to the three surfaces is less than 30'; and (3) the blunt radius R at the intersection of the indenters is not greater than 0.1µm.

[0016] In one feasible implementation, the Vickers needle tip is required to have the following characteristics: (1) the cone angle is 136°±30' and the line angle is 148°6'±30'; (2) the bluntness R at the indenter intersection is not greater than 0.1µm.

[0017] In one feasible implementation, the combination accuracy of the diamond indenter and the quartz glass base must meet the following requirements: after the diamond micron indentation probe of this disclosure is assembled on the thermomechanical analyzer, the cone axis of the diamond indenter tip must be perpendicular to the quartz testing platform of the thermomechanical analyzer, and when pressed into the surface of the test sample, the inclination of the cone axis of the tip to the pressing direction is no more than 1 degree.

[0018] In one feasible embodiment, the diamond indenter has a mounting portion and a needle tip located at the lower end of the mounting portion, the mounting portion being bonded to or embedded in a mounting hole, and the needle tip extending from the bottom of a quartz glass base.

[0019] In one feasible implementation, the mounting portion includes a connecting middle portion and a pin tip disposed in the connecting middle portion.

[0020] In addition, the micron indentation testing equipment disclosed herein includes a thermomechanical analyzer equipped with the aforementioned diamond micron indentation probe. The thermomechanical analyzer has a quartz testing platform, wherein a thermocouple for temperature measurement is fixed on the quartz testing platform for detecting the actual temperature of the test sample.

[0021] In one feasible implementation, the thermomechanical analyzer equipped with the aforementioned diamond micron indentation probe has a Z-axis repeatability of no more than 0.1 μm, a displacement resolution of no more than 15 nm, an applied force of 0–1.0 N, and an applied force resolution of less than 1 mN.

[0022] Compared with the prior art, this disclosure includes at least the following beneficial effects:

[0023] (1) Using the thermomechanical analyzer disclosed herein to perform indentation tests on thin film materials at the micron scale can, to a certain extent, reflect the mechanical characteristics and thermomechanical properties of the composite material itself at the microscale, and eliminate the influence of possible film-forming defects on the mechanical properties of the thin film at the macroscale in ordinary tensile tests.

[0024] (2) By equipping the diamond micron indentation probe of this disclosure, the application range of thermomechanical analyzer is expanded. Compared with microhardness testing, this disclosure effectively uses the ability of TMA to test load force changes and indentation depth, realizing the application of the principle of ordinary nanoindentation technology at the micron scale. In addition to hardness testing, it can also calculate the elastic modulus of the material and evaluate the thermomechanical properties of the material under varying temperature conditions.

[0025] The diamond micron indentation probe disclosed herein has a quartz glass mounting rod. Compared with conventional metal mounting rods, quartz glass has a smaller coefficient of thermal expansion (0.5 ppm / K, compared to 10-20 ppm / K for metals), making it very suitable for the testing techniques disclosed herein.

[0026] Meanwhile, the diamond indenter has high hardness, which can meet the usage requirements. In addition, the diamond indenter and the quartz glass mounting rod are independent components, and the diamond indenter is easy to process into micron-sized needle tips.

[0027] (3) The cost of using the diamond micro-indentation probe disclosed herein on a thermomechanical analyzer is significantly lower than that of existing nano-indentation tests.

[0028] (4) In addition to characterizing the mechanical properties of composite films, diamond indenters can also be extended to other composite materials and even metal and ceramic materials. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0030] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of exemplary embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0032] Figure 1 This is a schematic diagram of the structure of the diamond micron indentation probe disclosed herein;

[0033] Figure 2 for Figure 1 An enlarged schematic diagram showing the specific installation structure of the diamond indenter;

[0034] Figure 3 This is a schematic diagram of the diamond micron indentation probe used in the detection process of this disclosure;

[0035] Figure 4 This is a schematic diagram of the cubic angle needle tip involved in this disclosure;

[0036] Figure 5 This is a schematic diagram of the Vickers needle tip involved in this disclosure;

[0037] Figure 6 This is a schematic diagram showing the needle tip in the pressed-in state, wherein... Figure 6 (a) shows an illustration of a Vickers needle tip. Figure 6 (b) shows the state when the needle tip is pressed in.

[0038] in, Figures 1 to 6 The correspondence between the reference numerals and component names in the attached drawings is as follows: 1. Quartz glass mounting rod; 2. Quartz glass base; 3. Mounting hole; 4. Diamond indenter; 41. Mounting part; 411. Connecting middle part; 412. Pin tip; 5. Pin tip; 6. Quartz test platform; 7. Test sample. Detailed Implementation

[0039] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0040] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0041] In view of the shortcomings of the prior art, this disclosure proposes a diamond microindentation probe. By replacing the existing probe with this diamond microindentation probe and mounting it on a thermomechanical analyzer, a microindentation testing device is formed, which can reflect the mechanical characteristics and thermomechanical properties of the material itself.

[0042] The diamond micron indentation probe will now be described in detail through specific embodiments.

[0043] Reference Figures 1 to 6 As shown, this disclosure provides a diamond micron indentation probe, including a quartz glass mounting rod 1, the quartz glass mounting rod 1 forming a quartz glass base 2, the quartz glass base 2 having a mounting hole 3, a diamond indenter 4 being installed in the mounting hole 3, and the bottom of the diamond indenter 4 being constructed as a micron-sized needle tip 5.

[0044] The mounting end of the quartz glass mounting rod 1 can adopt various design structures, the purpose of which is to effectively install and combine with the mounting carrier of the thermomechanical analyzer. In this disclosure, the quartz glass mounting rod 1 has a bent section at the top and the bottom can be connected to the mounting carrier of the corresponding thermomechanical analyzer without limiting its specific shape.

[0045] It should be noted that the quartz glass base 2 and the quartz glass mounting rod 1 can be integrally formed to create an integrated structure, thereby increasing the overall connection strength.

[0046] For example, the mounting hole 3 can be processed using diamond micro-drilling or laser. For example, the diamond indenter 4 can be installed in the mounting hole 3 by using a size-inlaid method, with the top end contacting the bottom of the hole to avoid deformation during thermal expansion. Within a small temperature range, such as within 300 degrees Celsius, high-temperature resistant adhesive can be used for bonding and fixing.

[0047] In this disclosure, the diamond indenter 4 is a precision-ground diamond indenter, and the micron-sized needle tip 5 at the bottom is a Vickers tip or a Brinell cubic angle tip. As an example, the diamond indenter 4 includes a mounting portion 41 and the needle tip 5 located at the lower end of the mounting portion. The mounting portion 41 is bonded to or embedded in the mounting hole 3, and the needle tip 5 extends from the bottom of the quartz glass base 2.

[0048] Specifically, the mounting part 41 includes a connecting middle part 411 and a pin tip 412 disposed on the connecting middle part 411. The connecting middle part 411 is used to connect the pin tip 412 and the bottom pin tip 5. The three are formed as a whole, constructing an integrated structure. This structure, combined with the material itself, has very high overall strength and can meet the requirements of use. The setting of the pin tip 412 allows the diamond indenter 4 to form a single-point contact with the bottom of the mounting hole 3 during installation, resulting in higher installation accuracy. If the diamond indenter 4 is set with a flat top instead of the pin tip 412, the flat top will be relative to the bottom plane, forming a plane-to-plane installation. However, plane-to-plane installation may not be accurate, especially since an accuracy error of 1-10 micrometers can affect the measurement results.

[0049] Because the diamond indenter 4 in this disclosure adopts the above-described structure, the middle connection part 411 in the middle section is much larger in size than the needle tips at both ends. This can effectively improve the overall connection strength of the diamond indenter 4 itself, and during installation, it can effectively increase the installation connection area, thereby increasing the connection firmness after installation and improving the overall tightness of the installation.

[0050] As a micrometer-scale diamond microindentation probe, in this disclosure, reference is made to Figure 6 The surface roughness of the needle tip 5 within 150 micrometers from the tip to the root must be less than 50 nm, and the depth of the needle tip 5 pressed into the test object is 1-130 μm.

[0051] Regarding the selection of the needle tip 5, the needle tip 5 can be constructed as a Vickers needle tip or a Brinell cubic angle needle tip. It should be noted that the effective needle tip height shall not be less than 150 micrometers.

[0052] Among them, for the Brinell cubic angle needle tip, the requirements are: (1) the included angle of the pyramidal surface is 65°18'±30', and the included angle of the line is 77°3'±30'; (2) the difference in the inclination angle of the central axis of the diamond indenter 4 relative to the three surfaces is less than 30'; (3) the blunt R of the indenter intersection is not greater than 0.1um.

[0053] For the Vickers needle tip, the requirements are: (1) the included angle of the pyramidal surface is 136°±30', and the included angle of the line is 148°6'±30'; (2) the blunt R of the indenter intersection is not greater than 0.1um.

[0054] Meanwhile, the combination accuracy of the diamond indenter 4 and the quartz glass base 2 must meet the following requirements: after the diamond micron indentation probe is assembled on the thermomechanical analyzer, the cone axis of the tip 5 of the diamond indenter 4 must be perpendicular to the quartz test platform 6 of the thermomechanical analyzer, and when pressed into the surface of the test sample 7, the inclination of the cone axis of the tip 5 to the pressing direction is no more than 1 degree.

[0055] After the diamond micron indentation probe is constructed according to the above design requirements, its tip 5 can reach the micron size level. When used in conjunction with a thermomechanical analyzer, it expands the application range of the thermomechanical analyzer and can perform indentation tests on thin film materials at the micron scale. To a certain extent, it can reflect the mechanical characteristics and thermomechanical properties of composite materials at the microscale, and eliminate the influence of possible film-forming defects on the mechanical properties of thin films at the macroscale in ordinary tensile tests.

[0056] This disclosure also provides a micron indentation testing device, including a thermomechanical analyzer equipped with the aforementioned diamond micron indentation probe. The thermomechanical analyzer has a quartz testing platform 6, wherein a thermocouple for temperature measurement is fixed on the quartz testing platform 6 for detecting the actual temperature of the test sample 7.

[0057] The accompanying TMA (Transient Actuation) device can be, for example, Mettler Toledo's TMA / SDTA 2+, with a Z-axis repeatability of no more than 0.1µm, a displacement resolution of no more than 15nm, an applied force of 0–1.0N, and a force resolution of less than 1mN. Alternatively, devices such as Netzsch's TMA 402 Hyperion and TA's TM 450 can also be used.

[0058] It should be noted that: using TMA and the aforementioned diamond microindentation probe, at least the elastic modulus of composite materials at the micron scale can be tested; using TMA analysis in conjunction with the aforementioned diamond microindentation probe, at least the hardness of composite film as a function of temperature can be tested.

[0059] The following section provides a specific example of a method for testing the elastic modulus of composite materials at the micrometer scale.

[0060] The method for testing the elastic modulus of the composite material at the micrometer scale includes the following steps:

[0061] S1: Assemble the diamond micro-indentation probe, place the polymer-ceramic composite film sample to be tested, and set the isothermal temperature T;

[0062] S2: Apply a small specific load P1, hold for time t0, and record the thickness h1 a in the Z-axis direction at this time; use this thickness as the zero point;

[0063] S3: Continue to apply a specific load P2, hold for time t0, and record the thickness h2a in the Z-axis direction at this time;

[0064] S4: Repeat the above steps until the maximum load Pmax, and record the thickness hmax in the Z-axis direction at this time to obtain a set of correspondences between the load Pload and the thickness h {Pi, hia}.

[0065] S5; Unload to a specific load Pn, hold for a specific time t0, and record the thickness hnb at this time;

[0066] S6: Repeat the above steps until the minimum load P1, record the thickness h1b at this time, and obtain a set of correspondences between unloading load Punload and thickness h {Pi, hib}.

[0067] S7: Plot the loading-unloading Ph curve described above. Using the Oliver-pharr model and existing publicly available technical principles, the slope S and contact depth hc of the unloading curve can be calculated. Based on the contact depth hc and the contact area, a polynomial is fitted (considering the shapes of different indenters) to calculate the contact area Ac, thereby calculating the material's hardness (H) and simplified elastic modulus (Er). The calculation formula is:

[0068]

[0069] In this disclosure, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this disclosure according to the specific circumstances.

[0070] In the description of this disclosure, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0071] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0072] The above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A diamond micron indentation probe, characterized in that it comprises a quartz glass mounting rod, the quartz glass mounting rod forming a quartz glass base, the quartz glass base having a mounting hole, a diamond indenter being installed in the mounting hole, and the bottom of the diamond indenter being constructed as a micron-sized needle tip.

2. The diamond micron indentation probe according to claim 1, characterized in that, The diamond indenter is bonded or embedded in the mounting hole, and the needle tip protrudes from the bottom of the quartz glass base.

3. The diamond micron indentation probe according to claim 2, characterized in that, The surface roughness of the needle tip within 150 micrometers from the tip to the root must be less than 50 nm, and the depth to which the needle tip is pressed into the object to be tested is 1-130 μm.

4. The diamond micron indentation probe according to claim 3, characterized in that, The needle tip is constructed as a Vickers tip or a cubic angle tip, with an effective tip height of not less than 150 micrometers.

5. The diamond micron indentation probe according to claim 4, characterized in that, For the cubic angle needle tip, the requirements are: (1) the included angle of the pyramidal surface is 65°18'±30', and the included angle of the line is 77°3'±30'; (2) the difference in the inclination angle of the central axis of the diamond indenter relative to the three surfaces is less than 30'; (3) the blunt radius R of the indenter intersection is not greater than 0.1um.

6. The diamond micron indentation probe according to claim 5, characterized in that, For the Vickers needle tip, the requirements are: (1) the included angle of the pyramidal surface is 136°±30', and the included angle of the line is 148°6'±30'; (2) the blunt R of the indenter intersection is not greater than 0.1um.

7. The diamond micron indentation probe according to claim 6, characterized in that, The required precision of the combination of the diamond indenter and the quartz glass base is as follows: after the diamond micro-indentation probe is assembled on the thermomechanical analyzer, the cone axis of the diamond indenter tip must be perpendicular to the quartz testing platform of the thermomechanical analyzer, and when pressed into the surface of the test sample, the inclination of the cone axis of the tip to the pressing direction is no more than 1 degree.

8. The diamond micron indentation probe according to claim 7, characterized in that, The diamond indenter has a mounting part and a needle tip located at the lower end of the mounting part. The mounting part is bonded to or embedded in a mounting hole, and the needle tip extends from the bottom of the quartz glass base.

9. The diamond micron indentation probe according to claim 8, characterized in that, The mounting part includes a connecting middle part and a pin tip located in the connecting middle part.

10. A micrometer indentation testing device, comprising a thermomechanical analyzer equipped with a diamond micrometer indentation probe according to any one of claims 1 to 9, wherein the thermomechanical analyzer comprises a quartz testing platform, wherein a thermocouple for temperature measurement is fixed on the quartz testing platform for detecting the actual temperature of the test sample.

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