Atom-level defect-based structural superlubrication system and its manufacturing method

Abstract

This application provides a structural superlubricating system based on atomic-level defects and its manufacturing method. The structural superlubricating system includes a substrate material and a slider. Atomic-level defects are provided on the substrate material, and the slider is placed on the substrate material at the location of the atomic-level defects. The atomic-level defects enable different frictional forces between the slider and the substrate material when the slider slides along different directions. The atomic-level defects include planar discontinuities and / or material orientation discontinuities on the substrate material for the slider to slide. The manufacturing method of the structural superlubricating system includes providing a substrate material, manufacturing planar discontinuities by mechanical stripping, chemical etching, electron beam etching, atomic force microscopy probe etching, ion beam bombardment, or electron beam bombardment, or manufacturing orientation discontinuities by chemical vapor deposition, providing a slider, and placing the slider at the planar discontinuities or material orientation discontinuities.

Description

Technical Field

[0001] This application relates to the field of solid contact interface lubrication, and in particular to a structural superlubrication system based on atomic-level defects and its manufacturing method. Background Technology

[0002] Friction is prevalent in industrial production. It is estimated that approximately one-third of primary energy consumption in industrial production is related to friction processes, and friction and the resulting wear are the main causes of 80% of mechanical component failures. Effectively reducing friction and controlling wear is crucial for improving equipment reliability and achieving efficient energy utilization.

[0003] Structural superlubricity refers to the phenomenon where friction is almost zero at solid sliding interfaces due to incommensurable contact. When two crystal surfaces slide in incommensurable contact, the lateral forces between atoms cancel each other out, resulting in near-zero overall friction in the system. Although structural superlubricity has been observed in various material systems, effectively controlling the motion of the friction pair at a superlubricated interface with almost zero friction in all sliding directions remains a pressing problem. Existing experimental and theoretical studies show that for homogeneous or heterogeneous superlubricated systems, the sliding friction is relatively low in all sliding directions due to the incommensurable contact. In practical applications, how to control the relative motion of the interface and achieve directional superlubricating behavior without adding external constraints remains unknown. Summary of the Invention

[0004] This application provides a structural superlubrication system based on atomic-level defects and a method for manufacturing the same.

[0005] This super-lubricated system includes a substrate material and a slider. The substrate material has atomic-level defects, and the slider is placed on the substrate material at the locations of these atomic-level defects. These atomic-level defects allow the slider to slide along the substrate material in different directions, resulting in varying frictional forces between the slider and the substrate material.

[0006] The atomic-level defects include discontinuous areas on the substrate material where the slider slides and / or discontinuous areas in the material orientation.

[0007] In at least one embodiment, the substrate material includes a first structural layer and a second structural layer stacked together, the first structural layer being located above the second structural layer, the first structural layer and the second structural layer not completely overlapping, and a step structure forming between the first structural layer and the second structural layer, wherein the atomic-level defect includes the step structure.

[0008] The stepped structure includes a tread surface that is part of the base material and a riser surface that is perpendicular to the tread surface.

[0009] The surface of the base material includes a first direction and a second direction, the first direction being perpendicular to the boundary line between the kick surface and the tread surface of the stepped structure, and the second direction being along the boundary line.

[0010] In at least one embodiment, the step structure includes a single atomic-level step, the slider is located on the single atomic-level step, and the slider simultaneously contacts the first structural layer and the second structural layer.

[0011] The frictional force of the slider traveling in a direction other than the second direction is greater than the frictional force traveling in the second direction.

[0012] In at least one embodiment, the step structure comprises at least two atomic-level steps.

[0013] In at least one embodiment, the stepped structure includes two atomic-level steps parallel to the kick surfaces of the same layer, the slider is disposed on the two atomic-level steps parallel to the kick surfaces of the same layer, and the slider contacts the first structural layer.

[0014] The frictional force of the slider traveling in a direction other than the second direction is greater than the frictional force traveling in the second direction.

[0015] In at least one embodiment, the substrate material includes a third structural layer located below the second structural layer. The stepped structure includes two atomic-level steps parallel to the risers of the different layers. The slider is disposed on the two atomic-level steps parallel to the risers of the different layers, and the slider contacts the first structural layer, the second structural layer, and the third structural layer.

[0016] The frictional force of the slider traveling in a direction other than the second direction is greater than the frictional force traveling in the second direction.

[0017] In at least one embodiment, the stepped structure comprises two atomic-level steps with intersecting risers, the included angle between the two risers being not less than 30°.

[0018] When the slider is positioned at the intersection of two atomic-level steps where the kick surfaces intersect, the frictional force of the slider traveling in any direction within the surface of the substrate material is greater than the frictional force between the slider and the substrate material in a super-lubricated state.

[0019] In at least one embodiment, the atomic-level defect includes a grain boundary, and the slider is disposed on the grain boundary.

[0020] The frictional force of the slider traveling along the grain boundary extension direction is less than the frictional force of the slider traveling in other directions.

[0021] In at least one embodiment, the atomic-level defect includes an atomic-level vacancy defect, and the slider is disposed on the atomic-level vacancy defect.

[0022] The frictional force of the slider traveling along the extension direction of the atomic-level vacancy defect is less than the frictional force of the slider traveling perpendicular to the extension direction of the atomic-level vacancy defect.

[0023] This application provides a method for manufacturing the above-mentioned superlubricating system based on atomic-level defects, which includes: providing the substrate material;

[0024] The planar discontinuities are created on the substrate material by means of mechanical stripping, chemical etching, electron beam etching, atomic force microscopy probe etching, ion beam bombardment, or electron beam bombardment.

[0025] Provide the slider; and

[0026] The slider is placed at a point where the plane is discontinuous.

[0027] This application also provides another method for manufacturing the above-mentioned superlubricating system based on atomic-level defects, which includes: providing the substrate material;

[0028] The method of chemical vapor deposition is used to create regions with discontinuous material orientation on the substrate material;

[0029] Provide the slider; and

[0030] The slider is placed at a location where the material orientation is discontinuous.

[0031] The atomic-level defects are prepared by means of mechanical stripping, chemical etching, electron beam etching, atomic force microscopy probe etching, ion beam bombardment, electron beam bombardment, or chemical vapor deposition.

[0032] The structural superlubrication system proposed in this application achieves anisotropy of frictional performance by introducing atomic-level defects at the superlubrication interface, thereby enabling active control over the motion direction of the friction pair.

[0033] The super-lubricated structural system manufactured by the manufacturing method provided in this application has the aforementioned advantages. Attached Figure Description

[0034] Figure 1A , Figure 1B , Figure 1C , Figure 1DA schematic diagram of four atomic-level steps of the superlubricating system according to Embodiment 1 of this application is shown.

[0035] Figure 2A , Figure 2B , Figure 2C , Figure 2D A schematic diagram of the slider of the superlubricated system according to Embodiment 1 of this application is shown, located on an atomic-level step.

[0036] Figure 3A , Figure 3B A schematic diagram of the grain boundary of the superlubricating system according to Embodiment 2 of this application and a schematic diagram of the slider located on the grain boundary are shown.

[0037] Figure 4A , Figure 4B A schematic diagram of an atomic-level vacancy defect in a super-lubricating system according to Embodiment 3 of this application and a schematic diagram of a slider located on an atomic-level vacancy defect are shown.

[0038] Explanation of reference numerals in the attached figures

[0039] 1. Substrate material;

[0040] 2. A single atomic-level step;

[0041] 3. Two atomic-level steps parallel to the risers on the same layer;

[0042] 4. Two atomic levels parallel to the kick surfaces located in different layers;

[0043] 5. Two atomic-level steps intersecting the risers;

[0044] 6 sliders;

[0045] 7. Grain boundaries;

[0046] 8 Atomic-level vacancy defects Detailed Implementation

[0047] Exemplary embodiments of this application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement this application only, and are not intended to exhaustively describe all possible methods of this application, nor to limit the scope of this application.

[0048] This application provides a structural superlubricating system based on atomic-level defects (hereinafter, sometimes referred to as the "control method") and its manufacturing method, which is used to solve the problem that the friction between the slider and the substrate material in existing structural superlubricating systems is isotropic, making it difficult to directionally control or anchor the motion behavior of the friction pair.

[0049] The structural superlubrication system may include a substrate material 1 and a slider 6. Atomic-level defects may include planar discontinuities and / or material orientation discontinuities on the substrate material 1 where the slider 6 slides, where "atomic-level" refers to the size order of the defect. Atomic-level defects can be step structures, grain boundaries, atomic-level vacancy defects, etc., located on the substrate material 1. By placing the slider 6 on the atomic-level defects, the frictional properties between the slider 6 and the substrate material 1 can be controlled; for example, the magnitude of the frictional force between the slider 6 and the substrate material 1 can vary when the slider 6 slides along different directions on the substrate material 1.

[0050] Example 1

[0051] Active control of superlubricating behavior can be achieved by introducing atomically high steps at the superlubricating interface of the structural superlubricating system. The base material 1 may include a first structural layer and a second structural layer stacked together, not completely overlapping, forming a stepped structure between them. The first structural layer is located above the second structural layer. The stepped structure may include a tread surface, which is part of the surface of the base material 1, and a kick surface perpendicular to the tread surface (not shown in the figure). The surface of the base material 1 is the surface used to mount the slider 6. On the plane containing the base material 1, the direction perpendicular to the boundary line between the kick surface and the tread surface is defined as the first direction X, and the direction along this boundary line is defined as the second direction Y.

[0052] For example, a method for manufacturing a structural superlubrication system that uses steps as a control means may include the following steps.

[0053] Step 1: Select a material with super-lubricating properties as the base material 1, such as natural graphite with a layered structure or highly oriented pyrolytic graphite (HOPG);

[0054] Step 2: A stepped structure with atomic-level height is prepared on the surface of substrate material 1 by mechanical exfoliation. Four typical atomic-level stepped structures are shown below. Figure 1A , Figure 1B , Figure 1C , Figure 1D As shown, there are two atomic-level steps: 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 1 ... Figure 1B The groove width of the two parallel atomic-level steps in the middle and Figure 1C The distance between the two parallel atomic-level steps in the middle can be 10 nm to 100 nm. Figure 1DThe angle between intermediate atomic-level steps can be from 30° to 90°; of course, the above steps can also be prepared by chemical etching, electron beam etching and atomic force microscopy probe etching.

[0055] Step 3: Deposit a metal thin film of a certain thickness (e.g., 0.1 nm to 1 nm) on the steps of the substrate material 1 with atomic-level steps by metal deposition methods such as vapor deposition or electron beam deposition;

[0056] Step 4: The metal film is subjected to high-temperature annealing (temperature, for example, 350–500 degrees Celsius) under a protective atmosphere of inert gas (e.g., argon and hydrogen) to obtain a metal slider 6 with nanometer-scale dimensions, such as... Figure 2A , Figure 2B , Figure 2C , Figure 2D As shown, the lateral area of ​​slider 6 obtained by this method (or the area of ​​the plane of slider 6 parallel to the surface of substrate material 1) can be 500 nm. 2 up to 10000 nm 2 Of course, the pre-prepared slider 6, which is located in another position, can also be moved to the top of the atomic-level step by manipulating the probe of the atomic force microscope; of course, other sliders with super-lubricating properties can also be selected, such as super-lubricating sliders made of layered materials such as graphite and graphene.

[0057] The sliding behavior of slider 6, located above different types of atomic-level steps, will be affected by the atomic-level steps, exhibiting different sliding behaviors.

[0058] like Figure 2A As shown, when slider 6 is positioned above a single atomic-level step 2, slider 6 simultaneously contacts both the first and second structural layers. At this time, the frictional force when slider 6 moves along the second direction Y is relatively small (as indicated by the solid double arrows), still exhibiting superlubricity. The frictional force when slider 6 moves along other directions besides the second direction Y (e.g., the first direction X) is larger (as indicated by the dashed double arrows), and the higher the step, the greater the frictional force. The movement of slider 6 is restricted by the atomic-level steps, achieving directional superlubricity behavior.

[0059] like Figure 2B As shown, slider 6 can contact two atomic-level steps 3 parallel to the kick surfaces located in the same layer, and slider 6 contacts the first structural layer (in an optional scheme, slider 6 does not contact the second structural layer). Figure 2C As shown, the substrate material may also include a third structural layer, which is located below the second structural layer. The slider 6 can be positioned above two atomic levels 4 parallel to the kick surfaces of different layers, and simultaneously contact the first, second, and third structural layers.

[0060] It is understandable that in these two embodiments, the presence of two steps will further restrict the movement of slider 6 along non-second direction Y (e.g., first direction X) (as shown by the double-headed dashed lines), but movement along the second direction Y can still maintain a super-lubricated state (as shown by the double-headed solid lines), thus slider 6 can achieve directional super-lubricated behavior. It should be noted that compared to a single atomic-level step 2, the presence of two parallel-faced atomic-level steps will result in higher frictional forces on the slider when moving along non-second direction Y (e.g., first direction X), thus significantly restricting its movement. Of course, there can be more layers of parallel-faced atomic-level steps.

[0061] like Figure 2D As shown, slider 6 can contact the intersection point of two atomic-level steps 5 where the kick surfaces intersect. The angle between the kick surfaces of the two steps can be no less than 30°. In this case, the presence of the steps will significantly increase the friction of slider 6 in all directions, limiting the super-lubricated behavior of slider 6 in all directions. Slider 6 will be anchored to a certain extent at the intersection point of the atomic-level steps. In particular, when the angle between the kick surfaces of the two steps is 90°, the friction force on slider 6 is relatively large.

[0062] In summary, by introducing different types of atomic-level steps at the superlubricated interface, different effects can be achieved on the surface friction of the superlubricated structural system. For example, introducing a single atomic-level step or two atomic-level steps with parallel kick surfaces can achieve directional superlubricated sliding; while introducing two atomic-level steps with intersecting kick surfaces can restrict the sliding behavior of the interface in various directions, thereby controlling the behavior of the superlubricated interface.

[0063] Example 2

[0064] See Figure 3A , Figure 3B Furthermore, grain boundaries 7 can be used to replace steps. A grain boundary 7 will form in materials with the same structure but different orientations. When slider 6 moves above grain boundary 7, it produces a friction control effect similar to a single atomic-level step 2. The frictional force of slider 6 traveling along the extension direction of grain boundary 7 is less than the frictional force of slider 6 traveling in other directions. Figure 3A The arrows in the diagram indicate the orientation of the material. Grain boundaries 7 can be prepared by chemical vapor deposition.

[0065] Example 3

[0066] See Figure 4A , Figure 4BFurthermore, atomic-level vacancy defects 8 can be used to replace steps. Controllable atomic-level vacancy defects 8 can be prepared on the surface of materials with the same material and orientation by bombardment with ion beams or electron beams. Moving the slider 6 above these atomic vacancy defects can produce a friction-controlled effect similar to two parallel atomic-level steps 3 located on the same layer. The frictional force of the slider 6 traveling along the extension direction of the atomic-level vacancy defect 8 is less than the frictional force of the slider 6 traveling in other directions (e.g., perpendicular to the extension direction of the atomic-level vacancy defect 8). Of course, more complex atomic-level vacancy defects can be prepared to achieve even more friction-controlled effects.

[0067] This application achieves anisotropy of frictional properties by introducing atomic-level defects at the superlubricated interface, thereby enabling active control of the friction pair's motion. For example, depending on the type of atomic-level step, one-dimensional directional (e.g., along the second direction Y) superlubricated motion can be achieved by introducing a single atomic-level step 2 or two atomic-level steps with parallel kick surfaces. Alternatively, two atomic-level steps 5 with an included angle can be introduced to restrict motion in various sliding directions, providing a novel strategy for the active control of superlubricity in practical applications.

[0068] Of course, metal can also be used as the base material, and graphite with super-lubricating properties can be used as the slider. The aforementioned atomic-level defects can still be effective at this sliding interface.

[0069] It is understood that the parameters listed in this application are only some typical parameters, and this application does not limit the specific parameters of the slider and the substrate material.

[0070] Although this application has been described with reference to exemplary embodiments, it should be understood that this application is not limited to the disclosed exemplary embodiments. Those skilled in the art can make various modifications and changes to the above embodiments based on the teachings of this application without departing from the scope of this application. Supplementary descriptions are provided below.

[0071] i. In this application, for the convenience of explaining and understanding the technical solution, the two mutually perpendicular planes of the step are named "tread" and "rising surface", but these two surfaces do not actually realize the so-called stepping function.

[0072] ii. In this application, “parallel” and “perpendicular” do not strictly follow the definition in the sense of macroscopic geometry, but rather conform to the understanding of parallelism and perpendicularity by those skilled in the art in the field of superlubricity regarding the atomic-level defect structure.

Claims

1. A superlubricating system based on atomic-level defects, characterized in that, The super-lubricating system includes a base material (1) and a slider (6). The base material (1) has atomic-level defects. The slider (6) is placed on the base material (1) and located at the location of the atomic-level defects. The atomic-level defects enable the slider (6) to slide on the base material (1) in different directions, resulting in different magnitudes of friction between the slider (6) and the base material (1). The atomic-level defects include discontinuous areas on the substrate material (1) where the slider (6) slides and / or discontinuous areas in the material orientation. The substrate material (1) includes a first structural layer and a second structural layer stacked together. The first structural layer is located above the second structural layer. The first structural layer and the second structural layer do not completely overlap, and a step structure is formed between the first structural layer and the second structural layer. The atomic-level defects include the step structure. The stepped structure includes a tread surface that is part of the surface of the base material (1) and a riser surface that is perpendicular to the tread surface. The surface of the base material (1) includes a first direction (X) and a second direction (Y), the first direction (X) being perpendicular to the boundary line between the riser and the tread of the stepped structure, and the second direction (Y) being along the boundary line.

2. The superlubricating system based on atomic-level defects according to claim 1, characterized in that, The stepped structure includes a single atomic-level step (2), the slider (6) is located on the single atomic-level step (2), and the slider (6) simultaneously contacts the first structural layer and the second structural layer. The frictional force of the slider (6) traveling in a direction other than the second direction (Y) is greater than the frictional force traveling in the second direction (Y).

3. The superlubricating system based on atomic-level defects according to claim 1, characterized in that, The step structure includes at least two atomic-level steps.

4. The superlubricating system based on atomic-level defects according to claim 3, characterized in that, The stepped structure includes two atomic-level steps parallel to the kick surfaces of the same layer. The slider (6) is disposed on the two atomic-level steps parallel to the kick surfaces of the same layer, and the slider (6) contacts the first structural layer. The frictional force of the slider (6) traveling in a direction other than the second direction (Y) is greater than the frictional force traveling in the second direction (Y).

5. The superlubricating system based on atomic-level defects according to claim 3, characterized in that, The substrate material (1) includes a third structural layer located below the second structural layer. The stepped structure includes two atomic-level steps parallel to the kick surfaces of different layers. The slider (6) is disposed on the two atomic-level steps parallel to the kick surfaces of different layers, and the slider (6) contacts the first structural layer, the second structural layer, and the third structural layer. The frictional force of the slider (6) traveling in a direction other than the second direction (Y) is greater than the frictional force traveling in the second direction (Y).

6. The superlubricating system based on atomic-level defects according to claim 3, characterized in that, The stepped structure includes two atomic-level steps where the risers intersect, and the included angle between the two risers is not less than 30°. When the slider (6) is positioned at the intersection of two atomic-level steps where the kick surfaces intersect, the frictional force of the slider (6) traveling in any direction within the surface of the base material (1) is greater than the frictional force between the slider (6) and the base material (1) in a super-lubricated state.

7. The superlubricating system based on atomic-level defects according to claim 1, characterized in that, The atomic-level defects include grain boundaries (7), and the slider (6) is disposed on the grain boundaries (7). The frictional force of the slider (6) traveling along the extension direction of the grain boundary (7) is less than the frictional force of the slider (6) traveling in other directions.

8. The superlubricating system based on atomic-level defects according to claim 1, characterized in that, The atomic-level defects include atomic-level vacancy defects (8), and the slider (6) is disposed on the atomic-level vacancy defects (8). The frictional force of the slider (6) traveling along the extension direction of the atomic-level vacancy defect (8) is less than the frictional force of the slider (6) traveling along the extension direction perpendicular to the atomic-level vacancy defect (8).

9. A method for manufacturing a superlubricating system based on atomic-level defects according to any one of claims 1 to 8, characterized in that, The method includes: Provide the substrate material (1); The planar discontinuities are fabricated on the substrate material (1) by means of mechanical stripping, chemical etching, electron beam etching, atomic force microscope probe etching, ion beam bombardment or electron beam bombardment. Provide the slider (6); and The slider (6) is placed at the discontinuous part of the plane.

10. A method for manufacturing a superlubricating system based on atomic-level defects according to any one of claims 1 to 8, characterized in that, The method includes: Provide the substrate material (1); The material orientation discontinuity is created on the substrate material (1) by chemical vapor deposition growth method; Provide the slider (6); and The slider (6) is placed at the location where the material orientation is discontinuous.

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