A manufacturing method of a curved surface sensor integrated in a bearing and a design method of a stress buffering insulation layer

Abstract

The application provides a manufacturing method of a curved surface sensor integrated with a bearing and a design method of a stress buffer insulating layer, relates to the technical field of sensor manufacturing, and comprises the following steps: a micrometer-scale pit or groove array is processed on a nanometer-scale periodic stripe structure through a femtosecond laser; on the textured curved surface of the bearing, a composite process of alternately using an atomic layer deposition process and a magnetron sputtering process is adopted to alternately deposit an elastic modulus material sublayer and a toughness material sublayer, thereby generating a nanometer multilayer superlattice stress buffer insulating layer; based on first process parameters, a sensor pattern is scanned through the femtosecond laser according to a preset sensor pattern, thereby generating a sensing layer; based on second process parameters, the deposited sensing layer pattern is scanned through the femtosecond laser, thereby realizing local rapid annealing and generating a scanned sensor region; and on the scanned sensor region, a conformal protective layer is deposited through an atomic layer deposition process. The high-performance long-service-life sensor is manufactured in situ on the curved surface of the bearing.

Description

Technical Field

[0001] This invention relates to the field of sensor manufacturing technology, specifically to a method for manufacturing a curved surface sensor integrated into a bearing and a method for designing a stress-buffered insulating layer. Background Technology

[0002] Critical rolling bearings, such as the main bearings of aero-engines, operate in extremely harsh environments, facing multiple challenges including high temperatures (above 550°C), high speeds, heavy loads, and severe vibrations. Early bearing failure can lead to catastrophic consequences; therefore, achieving in-situ, real-time, and high-precision monitoring of their operating status is crucial for predictive maintenance and system safety. Key state parameters that need to be monitored include the local strain of the bearing raceways, temperature field distribution, and fretting displacements in the contact area between the rolling elements and the raceways. However, the internal space of aero-engines is extremely compact, and traditional external sensors (such as accelerometers and thermocouples) are insufficient to capture the true signals from the bearing itself. Furthermore, their leads are complex and bulky, failing to meet the requirements for high integration.

[0003] Currently, bearing condition monitoring sensing technologies for high-temperature environments mainly focus on three technical routes, but all have inherent drawbacks. Discrete high-temperature sensors (such as ceramic-encapsulated thermocouples and strain gauges) are manually installed and connected with leads. While they can withstand certain high temperatures, the consistency of manual manufacturing is poor, the probes are large, and the lead connection points are prone to becoming weak points in reliability under thermal cycling. Planar sensors based on thick-film printing technology have improved process consistency, but the silver-based paste used undergoes "silver migration" under high-temperature DC electric fields, easily leading to short circuits between coils and fatal failures. Furthermore, this process is inherently limited to planar substrates and cannot achieve high-precision patterning on the curved surface of the bearing. The most promising technology for achieving curved surface integration is thin-film sputtering based on physical masks, which involves patterning the bearing surface by attaching a precision metal mask to it. However, this approach faces two fundamental challenges: First, the rigid planar mask cannot perfectly fit the curved substrate, resulting in micron-level gaps that cause sputtering particles to scatter, leading to edge diffusion and linewidth loss (i.e., the "shadowing effect"), severely restricting the accuracy and performance consistency of the sensing element. Second, the significant mismatch in thermal expansion coefficients between the bearing substrate (steel) and the insulating layer (ceramic) generates significant interfacial thermal stress during high-temperature operation or cycling, easily causing the thin film layer to crack, peel, or even fail entirely. Furthermore, each bearing requires a custom-made, high-cost mask, resulting in poor process flexibility and making it difficult to adapt to the multi-specification, small-batch development characteristics of aerospace products.

[0004] In summary, the development of rolling bearing extreme environment health status monitoring sensing technology is evolving towards in-situ integration, structural flexibility, and digital manufacturing. However, existing technologies cannot simultaneously resolve the two core contradictions of high-precision patterning of curved surfaces and reliable integration with high-temperature heterogeneous interfaces. Therefore, there is an urgent need to develop an innovative manufacturing method that can eliminate the reliance on physical masks, fundamentally overcome pattern distortion, and optimize interface stress states to achieve reliable, flexible, and low-cost integration of high-performance sensors on complex curved bearing surfaces. Summary of the Invention

[0005] In view of this, embodiments of this specification provide a method for manufacturing a curved sensor integrated into a bearing and a method for designing a stress-buffered insulating layer, so as to achieve the purpose of in-situ integrated manufacturing of a high-temperature, high-reliability micro-sensing unit through femtosecond laser-induced material modification, selective chemical vapor deposition and nano-multilayer film stress control technology.

[0006] The embodiments in this specification provide the following technical solutions:

[0007] A method for manufacturing a curved surface sensor integrated into a bearing includes the following steps: Using femtosecond lasers, a nanoscale periodic stripe structure is induced on the target surface of the bearing substrate at an energy density lower than the material ablation threshold. At an energy density higher than the ablation threshold, micron-scale pits or groove arrays are fabricated on the nanoscale periodic stripe structure to generate a textured bearing surface. On the textured bearing surface, a composite process of alternating atomic layer deposition and magnetron sputtering is used to deposit elastic modulus material sublayers and toughness material sublayers alternately to generate a nano-multilayer superlattice stress buffer insulation layer. The first process parameters of the femtosecond laser-induced selective chemical vapor deposition process are set, the bearing is placed in a reaction chamber filled with precursor gas, and based on the first process parameters, the femtosecond laser is used to scan according to the preset sensor pattern, the precursor gas is decomposed at the laser focus, and a sensing layer pattern is deposited on the surface of the bearing to generate the sensing layer. The bearing with the deposited sensing layer is placed in an inert gas, and a second process parameter for local rapid annealing is set. Based on the second process parameter, the pattern of the deposited sensing layer is scanned by a femtosecond laser to achieve local rapid annealing and generate the scanned sensor area. In the post-scan sensor region, an atomic layer deposition process is used to deposit a conformal protective layer, which covers the surface of the nano-multilayer superlattice stress buffer insulation layer and the sensing layer, thus generating a curved sensor integrated into the bearing.

[0008] Furthermore, a nanoscale periodic stripe structure is induced on the target surface of the bearing substrate at an energy density below the material ablation threshold, and a micron-scale pit or groove array is fabricated on the nanoscale periodic stripe structure at an energy density above the ablation threshold, including: The period of the nanoscale periodic stripe structure is 500 nm to 800 nm; The depth of the micron-scale pit or trench array is 3 μm to 10 μm, and the diameter is 5 μm to 20 μm; The spacing between adjacent pits or grooves in the array is 10 μm to 30 μm.

[0009] Furthermore, a composite process alternating between atomic layer deposition and magnetron sputtering is employed to alternately deposit sublayers of elastic modulus material and toughness material, thereby generating a nano-multilayer superlattice stress-buffering insulating layer, including: The total thickness of the nano-multilayer superlattice stress-buffered insulating layer is 300 nm to 1.5 μm; The total number of layers, including the elastic modulus material sublayer and the toughness material sublayer, is 10 to 100. The elastic modulus material sublayer is made of one or more combinations of Al2O3, HfO2, and SiO2, and is prepared by atomic layer deposition process; The tough material sublayer is made of one or more combinations of Pt, TiN, and NiCrAlY, and is prepared by magnetron sputtering.

[0010] Furthermore, the first process parameters for the femtosecond laser-induced selective chemical vapor deposition process are set as follows: The laser wavelength was set to 515 nm to 800 nm, the pulse width to ≤500 fs, the laser power to 10 mW to 50 mW, the scanning speed to 0.5 mm / s to 5 mm / s, the precursor gas to carbonyl tungsten W(CO)6, carbonyl nickel Ni(CO)4, or an organic compound of nickel, and the reaction chamber pressure to 1 Torr to 20 Torr.

[0011] Furthermore, the deposited sensing layer pattern is one of the following: a high-temperature strain gauge pattern, a resistance temperature detector pattern, or a micro eddy current sensor pattern. The thickness of the sensing layer is 100 nm to 500 nm, and the linewidth is 5 μm to 20 μm.

[0012] Furthermore, the second process parameters for localized rapid annealing are set, including: Set the laser wavelength to 515 nm to 800 nm, the laser power to 1 mW to 10 mW, and the scanning speed to 0.5 mm / s to 5 mm / s.

[0013] Furthermore, the conformal protective layer is made of Al2O3 or SiO2 and has a thickness of 10 nm to 50 nm; The conformal protective layer is formed by atomic layer deposition at 150℃~300℃ and covers the surface of the nano-multilayer superlattice stress buffer insulation layer and the sensor pattern.

[0014] A design method for a nanoscale multilayer superlattice stress-buffered insulating layer, comprising the following steps: Obtain the design input parameters, including the coefficient of thermal expansion α of the bearing base material. sub The coefficient of thermal expansion α of the sensing layer material sense Operating temperature range ΔT, maximum allowable interfacial shear stress τ max The equivalent elastic modulus E of nano-multilayer superlattice structure eff ; Based on the thermal stress matching model, the minimum theoretical total thickness is calculated. ; Set the total design thickness of the nano-multilayer superlattice stress buffer insulation layer, such that the total design thickness is greater than or equal to the minimum theoretical total thickness and the absolute value of the overall residual stress of the nano-multilayer superlattice stress buffer insulation layer is less than or equal to the set maximum residual stress. The initial modulus material ratio and its variation law are set from the side closer to the bearing base to the side farther away from the bearing base. The modulus material ratio on the side closer to the bearing base is 0.2 to 0.5, and the modulus material ratio on the side farther away from the bearing base is 0.5 to 0.8. The variation law is one of linear gradient, parabolic gradient or step gradient. Determine the single-layer thickness of the elastic modulus material sublayer and the toughness material sublayer respectively; Based on the design total thickness, single-layer thickness, initial modulus material ratio and variation law, a nano-multilayer superlattice stress buffer insulation layer was deposited by alternating atomic layer deposition and magnetron sputtering processes, and the actual interfacial bonding force of the nano-multilayer superlattice stress buffer insulation layer was measured. Adjust the total design thickness, initial modulus material ratio, and variation pattern until the actual interface bonding force meets the set bonding force requirements.

[0015] Furthermore, the initial modulus material ratio and its variation law are defined from the side closer to the bearing base to the side farther from the bearing base, including: Obtain the interface roughness of the textured bearing surface; If the interface roughness is greater than the set roughness threshold, set the initial modulus material ratio to 0.2 to 0.3. If the interface roughness is less than or equal to the roughness threshold, set the initial modulus material ratio to 0.4 to 0.5. The thermal expansion coefficient α of the bearing base material sub The coefficient of thermal expansion α of the sensing layer material sense The difference in thermal expansion coefficients was calculated. If the difference in thermal expansion coefficients is less than or equal to the set minimum value, the variation pattern will be set to a linear gradient. If the difference in the coefficient of thermal expansion is between the set minimum and the set maximum values, the variation pattern will be set as a parabolic gradient. If the difference in thermal expansion coefficients is greater than or equal to the set maximum value, the change pattern will be set as a step gradient.

[0016] Further, the single-layer thicknesses of the elastic modulus material sublayer and the toughness material sublayer are determined, including: The first constraint is that the single-layer thickness of the elastic modulus material sublayer and the toughness material sublayer is less than or equal to the maximum single-layer thickness. The single-layer thickness of the elastic modulus material sublayer and the toughness material sublayer As a second constraint, b is the Burgers vector of the material system, with a value ranging from 0.25 nm to 0.35 nm, and f is the interface density parameter required for dislocation pinning, with a value of 0.02 nm. - ¹~0.05 nm - ¹; Based on the two thickness values ​​generated by the first and second constraints, the smaller of the two thickness values ​​is taken as the single-layer thickness.

[0017] Compared with the prior art, the beneficial effects that at least one technical solution adopted in the embodiments of this specification can achieve include at least: The method for manufacturing curved surface sensors according to embodiments of the present invention enables the in-situ manufacturing of high-performance, long-life sensors on the curved surface of bearings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of a method for manufacturing a curved surface sensor integrated into a bearing, according to an embodiment of the present invention. Figure 2 This is a schematic diagram of a femtosecond laser-induced generation of a nanoscale periodic stripe structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a nano-multilayer superlattice stress buffer insulation layer according to an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the principle of the femtosecond laser-induced selective chemical vapor deposition process according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the overall structure of the curved surface sensor integrated into the bearing according to an embodiment of the present invention. Detailed Implementation

[0020] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] like Figure 1 As shown, the technical solution of the present invention is achieved through the following core process steps: Laser surface texturing and chemical activation of bearing substrates: like Figure 2 As shown, the target curved surface of rolling bearing rings or related components is subjected to ultrasonic cleaning and electrochemical polishing to remove surface oxide scale. A femtosecond laser is then used to fabricate a micron-scale array of pits / grooves in the target area, generating a textured bearing surface. Simultaneously, by controlling the laser energy density below the material's ablation threshold, periodic nanostripes are induced on the microstructure surface. This micro / nano composite structure not only provides strong physical anchoring points for subsequent thin films but also, through the high surface energy of the nanostructure, allows for the chemical adsorption of more nucleation sites, laying the foundation for subsequent selective deposition.

[0023] Construction of a nano-multilayer superlattice stress-buffered insulating layer: like Figure 3 and Figure 4As shown, to fundamentally solve the problem of thermal expansion coefficient mismatch between the bearing substrate (usually steel) and the insulating and sensing layers (metallic materials), this invention further proposes a nano-multilayer transition layer design method based on the concept of functionally graded materials. Using a composite process of atomic layer deposition (ALD) and magnetron sputtering, a nano-multilayer superlattice stress-buffering insulating layer is alternately deposited on a textured surface. This layer consists of a high-elastic-modulus material (such as Al₂O₃, deposited by ALD with excellent shape retention) and a high-toughness material (such as Pt, TiN, deposited by magnetron sputtering). The thickness of a single layer (elastic-modulus material sublayer and toughness material sublayer) is controlled to <20 nm (maximum single-layer thickness is 20 nm). This nano-multilayer film (including elastic-modulus material sublayer and toughness material sublayer) possesses enormous interfacial energy, effectively pinning and hindering dislocation movement, and its comprehensive mechanical properties far exceed those of a single material. To fundamentally address the interfacial thermal stress caused by the mismatch in thermal expansion coefficients between the bearing substrate and the overlying sensing layer, the minimum total thickness of the transition layer is determined using a stress-thickness analytical model based on the difference in total thermal expansion coefficients between the bearing substrate and the sensing layer, the maximum allowable interfacial shear stress, and the operating temperature range (room temperature to 600℃). Typical values ​​are controlled between 300 nm and 1.5 μm. Simultaneously, the modulus ratio (ceramic ratio) (i.e., the proportion of the thickness of the elastic modulus sublayer to the total thickness) is monotonically adjusted from the bearing substrate side to the sensing layer side. The modulus ratio is lower (0.2-0.5) near the bearing substrate side to match the metal substrate, and higher (0.5-0.8) near the sensing layer side to ensure insulation and high-temperature stability. The variation can be linear, parabolic, or a stepped gradient. By adjusting the thickness ratio and spatial distribution of the modulus of different material layers, the overall equivalent thermal expansion coefficient of the multilayer film can be precisely controlled, achieving a gradual match from bottom to top with the metal of the bearing substrate and the upper sensing layer. This disperses the interfacial shear stress generated by thermal cycling throughout the entire transition layer thickness, avoiding local stress concentration. The overall residual stress of the transition layer does not exceed ±150 MPa (compressive stress is preferred), and the interface roughness (after laser texturing) is controlled within 50-200 nm to enhance mechanical interlocking and prevent peeling and cracking. The above design parameters can be precisely achieved for the thickness and modulus of each sublayer using alternating ALD / magnetron sputtering processes. Simultaneously, the ALD-deposited elastic modulus sublayer (Al2O3 layer) is dense and pinhole-free, providing excellent insulation properties.

[0024] Femtosecond laser-induced selective chemical vapor deposition for preparing sensing layers: The alternately deposited bearing is placed in a reaction chamber filled with a precursor gas (e.g., an organic compound of carbonyl tungsten W(CO)6 or nickel). A femtosecond laser beam is focused onto the curved surface of the bearing and scanned according to a pre-defined sensor pattern (e.g., a serpentine strain gauge or a spiral thermocouple). At the laser focal point, the extremely high photon density induces multiphoton absorption / nonlinear ionization, decomposing the precursor gas molecules and depositing high-purity metals (e.g., W, Ni) or compounds onto the locally heated substrate surface. The laser scanning path is the sensor pattern deposition path. By adjusting parameters such as laser power, scanning speed, and precursor gas pressure, the thickness and linewidth of the deposited layer can be precisely controlled (down to the submicron level). The entire process is a maskless, one-step fabrication of the sensing layer, avoiding the potential damage risk to the underlying insulating layer in traditional "deposition followed by etching" processes.

[0025] Femtosecond laser localized annealing and performance optimization: After the sensing layer is deposited, the deposited pattern is scanned again using a low-power femtosecond laser. The ultrafast heating and cooling effect of the femtosecond laser can rapidly anneal the sensing layer material locally, eliminating internal stress generated during deposition and transforming the film from an amorphous state to a polycrystalline state, significantly improving the stability of its temperature coefficient of resistance. This localized heat treatment method does not affect the performance of the bearing substrate and other areas.

[0026] Conformal deposited protective layer: A dense, conformal Al2O3 or SiO2 high-temperature protective layer (conformal protective layer) is deposited throughout the entire sensor area. The excellent conformal properties ensure that a pinhole-free, uniformly thick protective film can be formed even on micro-nano composite structures and complex curved surfaces.

[0027] The final manufactured curved sensor integrated into the bearing, such as... Figure 5 As shown.

[0028] Example 1: Step 1: Pretreatment and Laser Texturing of the Bearing Substrate: The bearing is placed on a five-axis platform. First, a low-power femtosecond laser (wavelength 515 nm, pulse width 300 fs) is used to scan the target area (inner raceway sidewall) to induce LIPSS nanostripes with a period of approximately 700 nm. Then, under the same optical path, the energy density is increased to above the ablation threshold to fabricate a micropore array with a depth of 5 μm, a diameter of 10 μm, and a spacing of 20 μm in the nanostripe region. Debris is removed by ultrasonic cleaning.

[0029] Step 2: Preparation of a Nanoscale Multilayer Superlattice Stress-Buffer Insulating Layer by ALD / Magnetron Sputtering 2: The bearing is placed in the ALD cavity, and a 5 nm elastic modulus material sublayer (such as Al2O3) is deposited at 200 °C using trimethylaluminum (TMA) and H2O as precursors. Then, it is transferred to the magnetron sputtering cavity to deposit a 5 nm toughness material sublayer (such as Pt). This cycle is repeated 50 times to form a 50 nm thick (Al2O3(5 nm) / Pt(5 nm)) 50 nm multilayer film. XRD analysis shows that the multilayer film exhibits clear superlattice satellite peaks.

[0030] Step 3: Femtosecond Laser-Induced Selective Chemical Vapor Deposition (FCVD) for Ni Strain Grating: A bearing with a nano-multilayer superlattice stress-buffered insulating layer is placed in a custom-designed stainless steel reaction chamber. After evacuation, a 5 Torr Ni precursor gas (Ni(CO)4) is introduced. A femtosecond laser (wavelength 800 nm, pulse width 100 fs) is focused on the bearing surface and scanned along a pre-defined serpentine strain grating CAD path. The laser power and scanning speed are optimized (e.g., power 20 mW, speed 1 mm / s) to ensure the deposition of pure Ni lines with a linewidth of approximately 10 μm and a thickness of approximately 200 nm. The light emission spectrum is monitored in real time during the deposition process to ensure the appearance of Ni characteristic peaks.

[0031] Step 4: Femtosecond Laser Local Annealing: The precursor gas in the reaction chamber is evacuated and replaced with argon. The power of the same femtosecond laser is reduced to 5mW, and the deposited Ni grating is scanned rapidly again. After treatment, the resistivity of the Ni film decreases, and the stability of the temperature coefficient of resistance (TCR) is improved.

[0032] Step 5: ALD Deposition of Protective Layer: Place the bearing back into the ALD cavity and deposit a 20 nm thick Al2O3 conformal protective layer at 250 °C.

[0033] Step Six: Post-processing and Testing: The bearing of the prepared sensor was vacuum annealed at 500 ℃ for 1 hour to further stabilize its performance. Tests showed that the sensor exhibited good linearity within the 20-600 ℃ range. After aging at 550 ℃ for 100 hours, the resistance drift was less than 0.2%, and no peeling or cracking of the film was observed.

[0034] Example 2: The rest is the same as in Example 1, except for the structure of the nano-multilayer superlattice stress buffer insulation layer 2. Specifically, initially, on the side closest to the bearing substrate, the single-layer thickness of the elastic modulus material sublayer (e.g., Al2O3) is 3 nm, and the single-layer thickness of the toughness material sublayer (Pt) is 7 nm (modulus ratio 0.3). As the deposition cycle proceeds, the deposition time is gradually adjusted so that the single-layer thickness of the elastic modulus material sublayer linearly increases to 7 nm and the single-layer thickness of the toughness material sublayer linearly decreases to 3 nm (modulus ratio 0.7).

[0035] Example 3: The rest is the same as in Example 1, except for the structure of the nano-multilayer superlattice stress buffer insulation layer 2. Specifically, initially, on the side closest to the bearing substrate, the single-layer thickness of the elastic modulus material sublayer (e.g., Al2O3) is 7 nm, and the single-layer thickness of the toughness material sublayer (Pt) is 3 nm (modulus ratio 0.7). As the deposition cycle proceeds, the deposition time is gradually adjusted so that the single-layer thickness of the elastic modulus material sublayer linearly decreases to 3 nm and the single-layer thickness of the toughness material sublayer linearly increases to 7 nm (modulus ratio 0.3).

[0036] The parameter comparisons for Examples 1, 2, and 3 are shown in Table 1.

[0037] Table 1 Parameter Comparison Table of Examples

[0038] Example 4: This embodiment provides a specific implementation method for designing a nano-multilayer superlattice stress-buffered insulating layer.

[0039] Obtain design input parameters. For materials using aero-engine bearing steel (such as GCr15) as the bearing base, the coefficient of thermal expansion α... sub ≈ 15×10 -6 / K; Using nickel (Ni) as the sensing layer material, its coefficient of thermal expansion α sense ≈ 13×10 -6 / K; Operating temperature range ΔT = 600℃ - 20℃ = 580K; Considering the high interfacial bonding strength of the nano-multilayer superlattice structure, the maximum allowable interfacial shear stress τ is taken. max = 2000 MPa; Equivalent elastic modulus E of nano-multilayer superlattice structure eff ≈20 GPa (estimated by the composite modulus of Al2O3 and Pt).

[0040] Secondly, the minimum theoretical total thickness is calculated based on the thermal stress matching model. The minimum theoretical total thickness h is calculated. min=11.6 nm. To provide higher structural reliability and process tolerance, the total design thickness h is set to... total = 1.2 μm (1200 nm), which is much larger than the minimum theoretical total thickness and can effectively disperse interfacial shear stress.

[0041] The overall residual stress is set as compressive stress, with an absolute value ≤ 150 MPa (target value - 100 MPa).

[0042] Then, the initial modulus material ratio (ceramic ratio) and its variation law were set. The roughness threshold was set to 100 nm. The interface roughness R of the textured bearing surface was obtained. a In this embodiment, R a = 80 nm (≤ roughness threshold), therefore the initial modulus material ratio on the side near the bearing substrate is set to 0.4 to 0.5, specifically 0.45.

[0043] Calculate the difference in thermal expansion coefficients Δα = |α sense - α sub | = 2×10 -6 / K. The minimum set coefficient Δα1 = 3 × 10 -6 / K, the maximum set coefficient Δα2 = 6 × 10 -6 / K. Since Δα ≤ 3×10 -6 / K, a linear gradient is chosen as the variation law, that is, the modulus material ratio increases linearly from 0.45 on the base side to 0.7 on the surface (far from the base side) (0.7 is taken in the range of 0.5 to 0.8).

[0044] Next, determine the thickness of each layer.

[0045] The first constraint is set: the thickness of the single layer of the elastic modulus material sublayer (Al2O3 layer) and the toughness material sublayer (Pt layer) is ≤20 nm (maximum single layer thickness).

[0046] Set a second constraint: Let b = 0.30 nm and f = 0.035 nm. - ¹, then b / (2f) = 0.3 / (2×0.035) = 0.3 / 0.07 ≈ 4.29 nm. Taking the smaller value of the first and second constraints, the upper limit of the single-layer thickness is 4.29 nm.

[0047] To satisfy the single-layer thickness constraint across the entire gradient range, it is necessary to ensure that the ceramic ratio is maximized (c sense When the elastic modulus is 0.70, the thickness of the sublayer of the elastic modulus material still does not exceed 4.29 nm. Let the total thickness of a single cycle be d. cycle Then the elastic modulus of the material sublayer corresponding to the maximum ceramic ratio = csense ×d cycle ≤4.29 nm, solving for d cycle ≤ 4.29 / 0.70 ≈ 6.13 nm. Take d... cycle = 6.0 nm, then when the ceramic ratio is 0.70, the thickness of the sublayer of the elastic modulus material is 4.2 nm and less than 4.29 nm, which satisfies the second constraint.

[0048] Based on the total design thickness h total =1200 nm and total thickness d of a single cycle cycle =6.0 nm, calculate the number of cycles N = 1200 / 6.0 = 200. Within each cycle: Initial cycle near the substrate: Elastic modulus material sublayer thickness = c sub ×d cycle =0.45×6.0=2.7 nm; Tough material sublayer thickness = (1-c sub )×d cycle =0.55×6.0=3.3 nm.

[0049] The final cycle near the surface: Elastic modulus material sublayer thickness = c sense ×d cycle =0.70×6.0=4.2 nm; Tough material sublayer thickness = (1-c sense )×d cycle =0.30×6.0=1.8 nm.

[0050] The monolayer thickness of all sublayers ranges from 2.7 nm to 4.2 nm, all less than 4.29 nm, satisfying both the first constraint (≤20 nm) and the second constraint (≤4.29 nm). With each deposition cycle, by progressively adjusting the deposition times of atomic layer deposition and magnetron sputtering, the Al2O3 layer thickness linearly increases from 2.7 nm to 4.2 nm, the Pt layer thickness linearly decreases from 3.3 nm to 1.8 nm, and the modulus materiality linearly increases from 0.45 to 0.70.

[0051] Next, the interfacial bonding strength was deposited and measured. Based on the design parameters (total design thickness 1200 nm, 200 cycles, total thickness per cycle 6.0 nm, linear gradient of modulus material rate from 0.45 to 0.70), a nanoscale multilayer superlattice stress-buffered insulating layer was deposited using alternating atomic layer deposition and magnetron sputtering. After deposition, the actual interfacial bonding strength was measured using a scratch test. The initial measurement result was 35 N, which did not meet the set requirement of 40 N.

[0052] Finally, iterative adjustments were made. Due to insufficient interfacial adhesion, the total design thickness was increased from 1200 nm to 1500 nm, while maintaining the total thickness d per cycle. cycle With the thickness remaining constant at 6.0 nm, the number of cycles N increases to 250, while the modulus material ratio variation pattern and range remain unchanged (still a linear gradient from 0.45 to 0.70). Increasing the total design thickness further disperses interfacial shear stress, thereby improving adhesion. The interfacial adhesion measured after redeposition was 46 N, meeting the requirement of ≥40 N. Furthermore, residual stress was measured using X-ray diffraction, yielding a result of -112 MPa (compressive stress), with an absolute value ≤150 MPa, meeting the design requirements.

[0053] Using the above design method, a nano-multilayer superlattice stress buffer insulation layer with excellent mechanical properties was successfully obtained. Its interfacial bonding force reached 46 N and the residual stress was -112 MPa, which is consistent with the experimental results of Example 2 (bonding force 46 N, residual stress -120 MPa), verifying the effectiveness and reliability of the design method.

[0054] Beneficial effects of the embodiments of the present invention: Compared to existing technologies that involve deposition followed by etching, this invention employs femtosecond laser-induced selective chemical vapor deposition (SCCVD) to achieve simultaneous deposition and patterning. This simplifies the process, avoids damage to the underlying film caused by etching, and the patterning accuracy is determined by the laser focus. It abandons the simple gradient buffer layer and adopts a nanoscale multilayer superlattice structure. Through quantum confinement and interface effects, it fundamentally solves the problems of thermal stress mismatch in heterogeneous materials and poor film-substrate adhesion, significantly improving reliability. The same femtosecond laser system achieves surface texturing, selective deposition, and localized annealing in this invention, greatly reducing equipment costs and enhancing process flexibility. Utilizing the nonlinear effects of femtosecond lasers, it enables multi-scale processing from macroscopic to nanoscale. Combined with atomic layer deposition (ALD) technology, it achieves perfect conformal coverage on extremely complex curved surfaces, providing unbreakable ultimate protection for sensors.

[0055] By introducing a nanoscale multilayer superlattice structure based on the concept of functionally graded materials, the modulus ratio (ceramic ratio) monotonically increases from 0.2–0.5 near the bearing substrate to 0.5–0.8 away from the substrate, achieving a gradual matching of the equivalent thermal expansion coefficient from the substrate side to the sensing layer side. Combined with a stress-thickness analytical model, the minimum theoretical total thickness is accurately calculated, dispersing the interfacial shear stress generated by thermal cycling throughout the entire transition layer thickness and avoiding local stress concentration. Experimental data show that the residual stress of the transition layer using this design method (ceramic ratio 0.3→0.7) is -120 MPa (compressive stress), and the interfacial bonding force reaches 46 N, significantly better than the schemes with constant ceramic ratio (-160 MPa, 28 N) and reverse gradient (+55 MPa tensile stress, 18 N).

[0056] This design methodology fully encompasses: acquiring input parameters, calculating the minimum theoretical thickness, setting the total design thickness and residual stress constraints, defining the range and pattern of modulus material ratio variation, determining the single-layer thickness based on dislocation pinning theory, depositing and measuring the interfacial bonding force, and iteratively adjusting parameters until the requirements (≥40 N) are met. This process upgrades traditional trial-and-error based experience to a scientific method of theoretical calculation and closed-loop verification, significantly shortening the R&D cycle, reducing trial-and-error costs, and ensuring the performance reliability of the final product.

[0057] By correlating the interface roughness of laser-textured surfaces with the initial modulus material rate, high-toughness materials preferentially fill the pits, forming a dual enhancement of mechanical interlocking and metallurgical bonding. This synergistic design fully leverages the physical anchoring effect of the micro / nano composite structure and the stress buffering effect of the gradient transition layer, achieving a technical effect of 1+1>2.

[0058] Based on the magnitude of the difference in thermal expansion coefficients, different ceramic ratio variation patterns are adaptively selected. This strategy enables the design method to be flexibly applied to the engineering needs of different material systems (different bearing steels, different sensing layer materials), exhibiting good universality and scalability.

[0059] This paper introduces dislocation pinning theory into the design of nanoscale multilayer superlattices. When the monolayer thickness is less than a critical value, the interfacial energy dominates the mechanical behavior, preventing dislocations from bowing out within the monolayer, thus significantly improving the yield strength and fatigue resistance of the multilayer film. This physical constraint transcends simple empirical numerical ranges, providing a solid theoretical foundation for the design method.

[0060] This design methodology includes not only forward design steps but also the measurement of actual interfacial bonding forces. If the requirements (≥40 N) are not met, parameters such as the total design thickness and modulus ratio are adjusted, and the single-layer thickness is recalculated. Deposition and measurement are repeated, forming a closed-loop feedback mechanism. This mechanism ensures the reliability of the final product's performance and avoids performance failures caused by theoretical calculation deviations or process fluctuations.

[0061] The design method of the nano-multilayer superlattice stress buffer insulation layer provided by this invention forms a complete, scientific and operable technical solution from theoretical model, parameter calculation, material selection, structural optimization to closed-loop verification. It effectively solves the problem of thermal stress mismatch at high-temperature heterogeneous interfaces in the prior art and significantly improves the reliability and service life of sensors under extreme working conditions.

[0062] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical solutions, and technical solutions in this invention can be freely combined and used.

Claims

1. A method for manufacturing a curved surface sensor integrated into a bearing, characterized in that, Includes the following steps: Using a femtosecond laser, a nanoscale periodic stripe structure is induced on the target surface of the bearing substrate at an energy density lower than the material ablation threshold. At an energy density higher than the ablation threshold, a micron-scale pit or groove array is fabricated on the nanoscale periodic stripe structure to generate a textured bearing surface. The initial modulus material ratio and its variation law are set from the side closer to the bearing substrate to the side farther away from the bearing substrate. The modulus material ratio is the proportion of the thickness of the elastic modulus material sublayer to the total thickness of the nano-multilayer superlattice stress buffer insulation layer. The modulus material ratio is 0.2 to 0.5 on the side closer to the bearing substrate and 0.5 to 0.8 on the side farther away from the bearing substrate. The variation law is one of linear gradient, parabolic gradient or step gradient. On the textured bearing surface, a composite process alternating between atomic layer deposition and magnetron sputtering is used to alternately deposit sublayers of elastic modulus material and toughness material to generate a nano-multilayer superlattice stress-buffering insulating layer, comprising: The total thickness of the nanoscale multilayer superlattice stress buffer insulating layer is 300 nm to 1.5 μm; the total number of the elastic modulus material sublayer and the toughness material sublayer is 10 to 100; the material of the elastic modulus material sublayer is one or more combinations of Al2O3, HfO2, and SiO2, and is prepared by atomic layer deposition; the material of the toughness material sublayer is one or more combinations of Pt, TiN, and NiCrAlY, and is prepared by magnetron sputtering. The first process parameters of the femtosecond laser-induced selective chemical vapor deposition process are set, the bearing is placed in a reaction chamber filled with precursor gas, and based on the first process parameters, the femtosecond laser is used to scan according to the preset sensor pattern, the precursor gas is decomposed at the laser focus, and a sensing layer pattern is deposited on the surface of the bearing to generate a sensing layer. The bearing with the deposited sensing layer is placed in an inert gas, and a second process parameter for local rapid annealing is set. Based on the second process parameter, the pattern of the deposited sensing layer is scanned by a femtosecond laser to achieve local rapid annealing and generate the scanned sensor area. In the post-scan sensor region, an atomic layer deposition process is used to deposit a conformal protective layer, which covers the surface of the nano-multilayer superlattice stress buffer insulation layer and the sensing layer, thereby generating a curved sensor integrated into the bearing.

2. The manufacturing method according to claim 1, characterized in that, The process involves inducing a nanoscale periodic stripe structure on the target surface of a bearing substrate using an energy density below the material ablation threshold, and then fabricating a micron-scale array of pits or grooves on the nanoscale periodic stripe structure using an energy density above the ablation threshold. This includes: The period of the nanoscale periodic stripe structure is 500 nm to 800 nm. The depth of the micron-scale pit or trench array is 3 μm to 10 μm, and the diameter is 5 μm to 20 μm; The spacing between adjacent pits or grooves in the array is 10 μm to 30 μm.

3. The manufacturing method according to claim 1, characterized in that, The first process parameters for femtosecond laser-induced selective chemical vapor deposition (FCVD) are set as follows: The laser wavelength was set to 515 nm to 800 nm, the pulse width to ≤500 fs, the laser power to 10 mW to 50 mW, the scanning speed to 0.5 mm / s to 5 mm / s, the precursor gas to carbonyl tungsten W(CO)6, carbonyl nickel Ni(CO)4, or an organic compound of nickel, and the reaction chamber pressure to 1 Torr to 20 Torr.

4. The manufacturing method according to claim 1, characterized in that, The deposited sensing layer pattern is one of a high-temperature strain gauge pattern, a resistance temperature detector pattern, or a micro eddy current sensor pattern. The thickness of the sensing layer is 100 nm to 500 nm, and the linewidth is 5 μm to 20 μm.

5. The manufacturing method according to claim 1, characterized in that, The second process parameters for localized rapid annealing are set, including: Set the laser wavelength to 515 nm to 800 nm, the laser power to 1 mW to 10 mW, and the scanning speed to 0.5 mm / s to 5 mm / s.

6. The manufacturing method according to claim 1, characterized in that, The conformal protective layer is made of Al2O3 or SiO2 and has a thickness of 10 nm to 50 nm. The conformal protective layer is formed by atomic layer deposition at 150°C to 300°C, and covers the surface of the nano-multilayer superlattice stress buffer insulation layer and the sensor pattern.

7. A design method for a nano-multilayer superlattice stress-buffering insulating layer, used to design the nano-multilayer superlattice stress-buffering insulating layer according to any one of claims 1 to 6, characterized in that, Includes the following steps: Obtain design input parameters, wherein the design input parameters include the coefficient of thermal expansion α of the bearing base material. sub The coefficient of thermal expansion α of the sensing layer material sense Operating temperature range ΔT, maximum allowable interfacial shear stress τ max The equivalent elastic modulus E of nano-multilayer superlattice structure eff ; Based on the thermal stress matching model, the minimum theoretical total thickness is calculated. ; The design total thickness of the nano-multilayer superlattice stress buffer insulation layer is set such that the design total thickness is greater than or equal to the minimum theoretical total thickness and the absolute value of the overall residual stress of the nano-multilayer superlattice stress buffer insulation layer is less than or equal to the set maximum residual stress. The initial modulus material ratio and its variation law are set from the side closer to the bearing base to the side farther away from the bearing base. The modulus material ratio on the side closer to the bearing base is 0.2 to 0.5, and the modulus material ratio on the side farther away from the bearing base is 0.5 to 0.

8. The variation law is one of linear gradient, parabolic gradient or step gradient. Determining the single-layer thickness of the elastic modulus material sublayer and the toughness material sublayer respectively includes: The first constraint is that the single-layer thickness of the elastic modulus material sublayer and the toughness material sublayer is less than or equal to the maximum single-layer thickness; the single-layer thickness of the elastic modulus material sublayer and the toughness material sublayer is... As a second constraint, b is the Burgers vector of the material system, with a value ranging from 0.25 nm to 0.35 nm, and f is the interface density parameter required for dislocation pinning, with a value of 0.02 nm. - ¹~0.05 nm - ¹; Based on the two thickness values ​​generated by the first constraint and the second constraint, the smaller of the two thickness values ​​is taken as the single-layer thickness; Based on the designed total thickness, the single-layer thickness, the initial modulus material ratio, and the variation law, the nano-multilayer superlattice stress buffer insulation layer is deposited by alternating atomic layer deposition and magnetron sputtering processes, and the actual interfacial bonding force of the nano-multilayer superlattice stress buffer insulation layer is measured. Adjust the total design thickness, the initial modulus material ratio, and the variation law until the actual interface bonding force meets the set bonding force requirements.

8. The design method according to claim 7, characterized in that, The initial modulus material ratio and its variation law are defined from the side closer to the bearing base to the side farther away from the bearing base, including: Obtain the interface roughness of the textured bearing surface; If the interface roughness is greater than the set roughness threshold, the initial modulus material ratio is set to 0.2 to 0.

3. If the interface roughness is less than or equal to the roughness threshold, the initial modulus material ratio is set to 0.4 to 0.5; The thermal expansion coefficient α of the bearing base material sub and the coefficient of thermal expansion α of the sensing layer material sense The difference in thermal expansion coefficients was calculated. If the difference in the coefficient of thermal expansion is less than or equal to the set minimum value, the change pattern is set as a linear gradient; If the difference in the coefficient of thermal expansion is between the set minimum value and the set maximum value, the variation law is set as a parabolic gradient; If the difference in the coefficient of thermal expansion is greater than or equal to the set maximum value, the change pattern is set as a step gradient.

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