High-temperature wear-resistant protective coating and preparation method and application thereof

Abstract

This invention relates to the field of surface engineering technology, and more particularly to a high-temperature wear-resistant protective coating, its preparation method, and its application. The high-temperature wear-resistant protective coating provided by this invention comprises layers I, II, III, IV, and V. This invention achieves a synergistic improvement in hardness and toughness through the amorphous-nanocrystalline composite structure of layers II and III and the Ni toughening transition layer of sublayer IV, overcoming the common problem of "the harder the coating, the more brittle it becomes" in traditional hard coatings. This invention achieves metallurgical bonding between the coating and the substrate through the coherent interface and elemental interdiffusion of layer V, with a film-substrate bonding strength exceeding 87.9 N. This invention eliminates the need for complex multilayer alternating deposition processes; a single step of plasma nitriding allows for the spontaneous formation of a finely structured, functionally distinct five-layer composite coating within a homogeneous Al-Cr-Ni metal coating. This in-situ self-formation mechanism greatly simplifies the preparation process and reduces production costs.

Description

Technical Field

[0001] This invention relates to the field of surface engineering technology, and in particular to a high-temperature wear-resistant protective coating, its preparation method, and its application. Background Technology

[0002] GH6159 is a Co-Ni-Cr based precipitation-strengthened superalloy. Through the synergistic effect of cold deformation and aging treatment, a γ′ strengthening phase precipitates in the matrix, introducing microstructures such as deformation twins and dislocation entanglements. This allows it to maintain ultra-high strength at around 600℃, while also exhibiting excellent fatigue resistance, corrosion resistance, and high-temperature oxidation resistance. Due to these comprehensive performance advantages, GH6159 has become an ideal material for manufacturing critical fasteners such as load-bearing bolts for aero-engines. However, GH6159 alloy has a significant performance drawback—low surface hardness. During bolt service, relative sliding and friction inevitably occur between the threaded pair and the bearing surface. The preload reduction caused by surface wear can lead to fastener loosening and failure, or even catastrophic accidents. Therefore, improving its surface tribological properties while maintaining the excellent matrix properties has become an urgent technical requirement.

[0003] To improve the wear resistance of component surfaces, researchers have developed surface coating technology. Among surface coating technologies, nitride hard coatings are widely used as protective coatings due to their excellent wear resistance, but they generally suffer from insufficient toughness, making them prone to crack initiation and propagation under load, ultimately leading to premature peeling and failure of the coating. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a high-temperature wear-resistant protective coating, its preparation method, and its application. This invention solves the problems of easy peeling and poor toughness of existing coatings under high-temperature service conditions, achieving a synergistic improvement in hardness, toughness, and bonding strength, and significantly improving its tribological properties at room temperature and 800℃.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a high-temperature wear-resistant protective coating, which is obtained by first depositing an Al-Cr-Ni metal layer on the surface of a GH6159 alloy substrate by magnetron sputtering, and then performing plasma nitriding treatment. From the surface inwards, the high-temperature wear-resistant protective coating sequentially comprises layer I, layer II, layer III, layer IV, and layer V; layer I is composed of CrN, Ni3Fe, and FeN. 0.0324 Phase composition; The second layer comprises Cr(Al)N and elemental Ni phase, and exhibits a gradient characteristic along the depth direction, with decreasing N content, increasing Ni content, and decreasing grain size. The third layer is an amorphous composite layer, comprising amorphous Al2O3 encapsulating Cr(Al)N and Ni nanocrystals; The IV layer is mainly composed of elemental Ni; The V layer forms a coherent interface with the GH6159 matrix.

[0006] Preferably, in the II layer, the upper layer is a coarse Cr(Al)N columnar crystal, and the lower layer is a composite structure in which Ni phase encapsulates Cr(Al)N nanocrystals.

[0007] Preferably, the high-temperature wear-resistant protective coating is metallurgically bonded to the GH6159 substrate, with a film-substrate bonding strength ≥87.9 N.

[0008] Preferably, the hardness of the high-temperature wear-resistant protective coating is above 25 GPa.

[0009] This invention provides a method for preparing the high-temperature wear-resistant protective coating described above, comprising the following steps: An Al-Cr-Ni metal coating was deposited on the surface of a GH6159 alloy substrate using magnetron sputtering, resulting in a substrate with the deposited Al-Cr-Ni metal coating. The magnetron sputtering conditions included: Al... 60 Cr 40 Target power 80~100 W, Ni target power >0 and ≤100 W, deposition temperature 300~370℃, bias voltage -50~-100 V, deposition time 5~10 h; The substrate with the deposited Al-Cr-Ni metal coating is subjected to plasma nitriding treatment to form layers I, II, III, IV and V in situ, thereby obtaining the high-temperature wear-resistant protective coating; The conditions for plasma nitriding treatment include: temperature 400~500℃, time 8~10 h, gas pressure 200~220 Pa, and atmosphere of NH3 or NH3-Ar mixed atmosphere.

[0010] Preferably, the Ni target power of the magnetron sputtering is 50 W.

[0011] Preferably, the flow ratio of NH3 to Ar in the NH3-Ar mixed atmosphere is 4:1 to 5:1.

[0012] Preferably, the magnetron sputtering gas pressure is 0.4~0.6 Pa, the duty cycle is 40~60%, the stage rotation speed is 2~5 r / min, and the target-substrate distance is 60~80 mm.

[0013] Preferably, the plasma nitriding treatment uses a glow discharge power supply with a glow discharge voltage of 680~720 V, a duty cycle of 40~60%, and a peak current maintained at 3~5 A.

[0014] This invention provides the application of the high-temperature wear-resistant protective coating described in the above-described scheme or the high-temperature wear-resistant protective coating prepared by the preparation method described in the above-described scheme in the surface protection of GH6159 high-temperature alloy load-bearing bolts of aero-engines.

[0015] The high-temperature wear-resistant protective coating provided by this invention includes layers I, II, III, IV, and V. Layer I is the outermost layer of the coating, and its main phases are CrN, Ni3Fe, and FeN. 0.0324 The first sublayer has low strength and can be rapidly ground to form beneficial wear debris in the early stages of friction and wear, acting as a "sacrificial layer." The second layer is the core structural layer of this invention, composed of a hard Cr(Al)N phase and a tough Ni phase, exhibiting a gradient characteristic along the depth direction: decreasing N content, increasing Ni content, and decreasing grain size. This gradient structure endows the coating with excellent comprehensive performance: the upper coarse grains can dissipate energy through intergranular shear slip under heavy loads, reducing stress concentration; the lower fine grains significantly improve hardness through the Hall-Petch effect, and high-density grain boundaries can prevent cracks from extending into the matrix. Simultaneously, the Ni phase can dissipate energy through shear deformation, hindering crack tip formation and propagation, achieving simultaneous optimization of hardness, strength, and toughness. The third layer is an amorphous composite layer, composed of amorphous Al2O3 encapsulating Cr(Al)N and Ni nanocrystals. This amorphous phase effectively hinders grain boundary slip during deformation, forming a composite structure with the nanocrystals to achieve a synergistic effect of high hardness and high toughness, helping to suppress crack propagation. Layer IV is a Ni-tough transition layer. This sublayer acts as a plastic buffer layer, absorbing and coordinating the strain transferred from the hard and brittle nitride coating to the metal substrate through its own plastic deformation. This prevents crack initiation at the interface due to strain incompatibility, improving the coating's thermal shock resistance and impact resistance. Layer V is a metallurgical bonding interface layer, which is the interdiffusion region between the coating and the GH6159 substrate. A coherent interface exists between this layer and the substrate, with parallel and equally spaced lattice fringes, no dislocation distribution, and low lattice mismatch. This structure significantly improves the interfacial separation work, effectively mitigating the thermal expansion mismatch effect between the two, which is the fundamental reason for the coating's high film-substrate adhesion.

[0016] This invention achieves a synergistic improvement in hardness and toughness through an amorphous-nanocrystalline composite structure in layers II and III and a Ni toughening transition layer in sublayer IV, overcoming the common problem of "the harder the coating, the more brittle it becomes" in traditional hard coatings. Through the coherent interface and elemental interdiffusion in layer V, this invention achieves a metallurgical bond between the coating and the substrate, with a film-substrate adhesion strength exceeding 87.9 N. This high adhesion strength ensures that the coating is not prone to peeling or failure under heavy load and high-temperature service conditions.

[0017] The high-temperature wear-resistant protective coating provided by this invention exhibits excellent tribological properties at both room temperature and 800°C. The wear rate at room temperature is reduced by 98.73% compared to the substrate, and the wear rate at 800°C is reduced by 92.10%. The dense enamel layer formed on the coating surface at high temperatures, in synergy with the incompletely oxidized CrN and AlN hard phases, provides superior high-temperature protection.

[0018] Furthermore, at high temperatures of 800℃, CrN coatings exhibit accelerated oxidation and a sharp decline in overall performance. This invention addresses the issues of high-temperature oxidation and insufficient toughness in CrN coatings through Al-Ni alloying, providing technical support for the engineering application of this process in the field of aerospace high-temperature fasteners.

[0019] This invention provides a method for preparing the high-temperature wear-resistant protective coating described above. This invention eliminates the need for complex multi-layer alternating deposition processes; instead, it achieves spontaneous formation of a finely structured, functionally distinct five-layer composite coating within a homogeneous Al-Cr-Ni metal coating through a single-step plasma nitriding treatment. This in-situ self-formation mechanism significantly simplifies the preparation process, reduces production costs, and offers strong process controllability and good reproducibility. Attached Figure Description

[0020] Figure 1 The cross-sectional SEM morphology and EDS surface scanning results of the GH6159+MS+PN sample are shown. Figure 2 The XRD pattern of the GH6159+MS+PN sample; Figure 3 Enlarged images of layer I and layer II, bright-field images, selected area electron diffraction (SAED) patterns, and high-resolution images; Figure 4 Enlarged images, bright-field images, SAED images, and high-resolution images of layers III, IV, and V; Figure 5 The bonding strength test results are for GH6159+MS and GH6159+MS+PN samples; Figure 6 The results of room temperature tribological tests on four samples, namely GH6159, GH6159+MS, GH6159+PN and GH6159+MS+PN, include friction coefficient curves, three-dimensional wear morphology and cross-sectional views. Figure 7 The results of the tribological and wear performance tests of four samples, namely GH6159, GH6159+MS, GH6159+PN and GH6159+MS+PN, at 800℃ include friction coefficient curves, three-dimensional wear morphology and cross-sectional views. Detailed Implementation

[0021] This invention provides a high-temperature wear-resistant protective coating, which is obtained by first depositing an Al-Cr-Ni metal layer on the surface of a GH6159 alloy substrate by magnetron sputtering, and then performing plasma nitriding treatment. From the surface inwards, the high-temperature wear-resistant protective coating sequentially comprises layer I, layer II, layer III, layer IV, and layer V; layer I is composed of CrN, Ni3Fe, and FeN. 0.0324 Phase composition; The second layer comprises Cr(Al)N and elemental Ni phase, and exhibits a gradient characteristic along the depth direction, with decreasing N content, increasing Ni content, and decreasing grain size. The third layer is an amorphous composite layer, comprising amorphous Al2O3 encapsulating Cr(Al)N and Ni nanocrystals; The IV layer is mainly composed of elemental Ni; The V layer forms a coherent interface with the GH6159 matrix.

[0022] In this invention, layer I is the outermost layer of the coating, and its main phases are CrN, Ni3Fe and FeN. 0.0324 This sublayer has low strength and can be rapidly ground to form beneficial wear debris in the early stages of friction and wear, thus acting as a "sacrificial layer".

[0023] In this invention, layer II is composed of a hard Cr(Al)N phase and a tough Ni phase, and has a gradient characteristic of "decreasing N content, increasing Ni content, and decreasing grain size" along the depth direction. In this invention, layer II has an upper layer of coarse Cr(Al)N columnar crystals and a lower layer of a composite structure of Ni phase-encapsulated Cr(Al)N nanocrystals. In embodiments of this invention, the width of the upper grains is preferably 175-185 nm, and the width of the lower grains is preferably 45-55 nm. In this invention, the Ni content on the upper surface of layer II is preferably 26.47-28.81 at.%, and the Ni content on the lower surface is preferably 32.58-33.94 at.%. In this invention, the N content on the upper surface of layer II is preferably 28.89-29.64 at.%, and the N content on the lower surface is preferably 24.74-26.51 at.%.

[0024] In this invention, the gradient structure of layer II endows the coating with excellent comprehensive performance: the coarse grains in the upper layer can dissipate energy through intergranular shear slip under heavy load, reducing stress concentration; the fine grains in the lower layer significantly improve hardness through the Hall-Petch effect, and the high-density grain boundaries can prevent cracks from extending into the matrix. At the same time, the Ni phase can consume energy through shear deformation and hinder the formation and propagation of crack tips, thus achieving simultaneous optimization of hardness, strength and toughness.

[0025] In this invention, layer III is an amorphous composite layer comprising amorphous Al₂O₃ encapsulating Cr(Al)N and Ni nanocrystals. This amorphous phase effectively hinders grain boundary slip during deformation, forming a composite structure with the nanocrystals to achieve a synergistic effect of high hardness and high toughness, thus helping to suppress crack propagation. In this invention, sublayer III is predominantly enriched with Al and O elements.

[0026] In this invention, layer IV is mainly composed of elemental Ni. The Ni content in layer IV is preferably 60-70 at.%. Layer IV is a Ni-toughness transition layer. This sublayer acts as a plastic buffer layer, absorbing and coordinating the strain transferred from the hard and brittle nitride coating to the metal substrate through its own plastic deformation. This prevents crack initiation at the interface due to strain incompatibility, thereby improving the coating's thermal shock resistance and impact resistance.

[0027] In this invention, layer V forms a coherent interface with the GH6159 substrate. Layer V is enriched in Ni and contains small amounts of Co, Cr, Fe, Mo, and Ti elements dissolved from the substrate. Layer V represents the interdiffusion region between the coating and the GH6159 substrate. A coherent interface exists between this layer and the substrate, with parallel and equally spaced lattice fringes at the interface, no dislocations, and low lattice mismatch. This structure significantly improves the interfacial separation work, effectively mitigates the thermal expansion mismatch effect between the two, and enhances the film-substrate adhesion of the coating.

[0028] In this invention, the high-temperature wear-resistant protective coating is metallurgically bonded to the GH6159 substrate, and the film-substrate adhesion is preferably ≥87.9 N. In this invention, the hardness of the high-temperature wear-resistant protective coating is preferably ≥25 GPa, and in one specific embodiment, it is 26.47 GPa.

[0029] In this invention, the thickness of the high-temperature wear-resistant protective coating is preferably 2.5~2.7 μm, more preferably 2.6 μm.

[0030] This invention provides a method for preparing the high-temperature wear-resistant protective coating described above, comprising the following steps: depositing an Al-Cr-Ni metal coating on the surface of a GH6159 alloy substrate by magnetron sputtering to obtain a substrate with the Al-Cr-Ni metal coating deposited; the magnetron sputtering conditions include: Al 60 Cr 40 Target power 80~100 W, Ni target power 0~100 W, deposition temperature 300~370℃, bias voltage -50~-100 V, deposition time 5~10 h; The substrate with the deposited Al-Cr-Ni metal coating is subjected to plasma nitriding treatment to form a five-layer structure in situ, thereby obtaining the high-temperature wear-resistant protective coating. The conditions for plasma nitriding treatment include: temperature 400~500℃, time 8~10 h, gas pressure 200~220 Pa, and atmosphere of NH3 or NH3-Ar mixed atmosphere.

[0031] In this invention, unless otherwise specified, the raw materials and equipment used are all commercially available products well known in the art.

[0032] This invention employs magnetron sputtering to deposit an Al-Cr-Ni metal coating on the surface of a GH6159 alloy substrate, thereby obtaining a substrate with the deposited Al-Cr-Ni metal coating.

[0033] Before depositing the Al-Cr-Ni metallic coating, the present invention preferably pre-treats the GH6159 alloy substrate. In the present invention, the pre-treatment preferably includes sequentially performing sandpaper grinding, polishing, and sandblasting on the GH6159 alloy substrate. In the present invention, the sandpaper grinding is preferably performed sequentially using 80-mesh, 240-mesh, 400-mesh, 800-mesh, 1200-mesh, 2000-mesh, and 3000-mesh SiC sandpaper. The present invention obtains a smooth and flat initial surface through sandpaper grinding and polishing.

[0034] This invention does not have special requirements for the sandblasting, as long as the surface roughness of the GH6159 alloy substrate after sandblasting is below 1.8 μm. In the embodiments of this invention, 80-mesh white corundum (Al2O3) is used as the sandblasting medium, the sandblasting air pressure is set to 0.3 MPa, the spray gun is perpendicular to the substrate surface at a distance of about 10 cm, and the sandblasting time is 10 s. After completing the sandblasting treatment, this invention preferably also includes ultrasonic cleaning of the sandblasted substrate with alcohol. This invention thoroughly removes residual sand particles adhering to the surface through ultrasonic cleaning.

[0035] In this invention, the conditions for magnetron sputtering include: Al 60 Cr 40 The target power is 80~100 W, the Ni target power is >0 and ≤100 W, the deposition temperature is 300~370℃, the bias voltage is -50~-100 V, and the deposition time is 5~10 h. In a specific embodiment, Al 60 Cr 40 The target power can be 80, 90, or 100 W; the Ni target power for magnetron sputtering can be 0, 30, 50, 80, or 100 W, preferably 50 W; the deposition temperature can be 300, 320, 350, or 370 °C; the bias voltage can be -50, -60, -70, -80, -90, or -100 V; and the deposition time can be 5, 6, 7, 8, 9, or 10 h. In this invention, the purity of the Ni target is preferably ≥99.95%.

[0036] In this invention, the gas pressure for magnetron sputtering is preferably 0.4~0.6 Pa, and in specific embodiments it can be 0.4, 0.5 or 0.6 Pa; the duty cycle for magnetron sputtering is preferably 40~60%, and in specific embodiments it can be 40%, 50% or 60%; the stage rotation speed for magnetron sputtering is preferably 2~5 r / min, and in specific embodiments it can be 2, 3, 4 or 5 r / min; the target-substrate distance for magnetron sputtering is preferably 60~80 mm, and in specific embodiments it can be 60, 70 or 80 mm. In this invention, the thickness of the Al-Cr-Ni metal coating is preferably 2.6 μm.

[0037] After obtaining the substrate with the Al-Cr-Ni metal coating deposited, the present invention performs plasma nitriding treatment on the substrate with the Al-Cr-Ni metal coating deposited to form layers I, II, III, IV and V in situ, thereby obtaining the high-temperature wear-resistant protective coating.

[0038] In this invention, the conditions for plasma nitriding treatment include: temperature 400~500℃, time 8~10 h, gas pressure 200~220 Pa, and atmosphere is NH3 or NH3-Ar mixed atmosphere.

[0039] In this invention, when the atmosphere is a mixture of NH3 and Ar, the flow ratio of NH3 to Ar is preferably 4:1 to 5:1, more preferably 5:1. In this invention, the plasma nitriding treatment preferably uses a glow discharge power supply, and the glow discharge voltage is preferably 680 to 720 V, which can be 680, 700, or 720 V in specific embodiments; the duty cycle is preferably 40 to 60%. In this invention, the peak current of the plasma nitriding treatment is preferably 3 to 5 A.

[0040] In the plasma nitriding process described in this invention, layers I, II, III, IV, and V are formed in situ.

[0041] In this invention, the main phases of the first layer are CrN, Ni3Fe and FeN. 0.0324 The formation mechanism is as follows: In the initial stage of plasma nitriding, due to the light weight of Al atoms and the high sputtering yield, a large amount of Al is stripped from the coating surface area, forming obvious Al-deficient regions; at the same time, Fe atoms sputtered from the steel cathode disk are deposited on the sample surface and combine with active N atoms to form FeN. 0.0324 Nitrides are formed; Cr and N on the coating surface react to form a CrN hard phase; under thermal activation, elements such as Co, Fe, Mo, and Ti in the matrix diffuse outward along the columnar grain boundaries and accumulate on the surface, among which Ni reacts with Fe to form the Ni3Fe phase. This sublayer has low strength and can be rapidly ground to form beneficial wear debris in the early stages of friction and wear, thus acting as a "sacrificial layer".

[0042] In this invention, layer II is composed of a hard Cr(Al)N phase and a tough elemental Ni phase. Its formation mechanism originates from the reverse diffusion behavior of N and Ni elements: during nitriding, N atoms gradually diffuse from the surface to the depth, forming a concentration gradient from top to bottom; while Ni has a weak affinity for N and is difficult to form stable nitrides. Driven by the thermodynamics of the nitrogen concentration gradient, Ni diffuses towards the bottom of the coating (low nitrogen potential region), forming a composition gradient from the surface to the core where the N content decreases and the Ni content increases.

[0043] The microstructure of layer II is characterized by: a lower Ni content (approximately 5-8 at.%) in the upper layer (near sublayer I) and sufficient nitrogen concentration, allowing Cr(Al)N grains to grow sufficiently and form coarse columnar crystals with a width of approximately 180 nm; and a higher Ni content (approximately 15-20 at.%) in the lower layer (near sublayer III), enriched at the Cr(Al)N grain boundaries, which not only significantly enhances the interference with columnar crystal growth but also activates grain re-nucleation, promoting the transformation of the structure from columnar crystals to dense nanocrystals. The bottom grains are refined to approximately 50 nm, forming a nanocomposite structure composed of a hard Cr(Al)N phase and a tough Ni phase. This gradient structure endows the coating with excellent comprehensive properties: the coarse columnar crystals in the upper layer can dissipate energy through intergranular shear slip under heavy loads, reducing stress concentration; the fine grains in the lower layer significantly improve hardness through the Hall-Petch effect, and the high-density grain boundaries can prevent cracks from extending into the matrix. At the same time, the Ni phase can dissipate energy through shear deformation and hinder crack tip formation and propagation, achieving simultaneous optimization of hardness, strength, and toughness.

[0044] In this invention, layer III is composed of amorphous Al₂O₃ encapsulating Cr(Al)N and Ni nanocrystals. Its formation is primarily regulated by the Gibbs interface energy difference and compositional segregation: when the interface energy difference between the amorphous and crystalline states is less than the interface energy difference between the crystalline states, the amorphous phase preferentially forms at the grain boundaries; simultaneously, some Al atoms segregate at the grain boundaries, forming a continuous amorphous AlN network, which is partially oxidized to amorphous Al₂O₃ in a high-temperature nitriding environment. This amorphous phase effectively hinders grain boundary slip during deformation, forming a composite structure with the nanocrystals to achieve a synergistic effect of high hardness and high toughness, thus helping to suppress crack propagation.

[0045] In this invention, layer IV is a region enriched with elemental Ni (Ni content approximately 60-70 at.%). Its formation mechanism is as follows: during nitriding, Ni in the coating diffuses towards the bottom, while Ni in the matrix diffuses towards the coating under thermal activation, accumulating at the interface due to the obstruction of the dense amorphous layer (layer III). This sublayer, acting as a plastic buffer layer, absorbs and coordinates the strain transferred from the hard and brittle nitride coating to the metal substrate through its own plastic deformation, preventing crack initiation at the interface due to strain incompatibility and improving the coating's thermal shock resistance and impact resistance.

[0046] In this invention, layer V is the interdiffusion region between the high-temperature wear-resistant protective coating and the GH6159 substrate. Under prolonged thermal activation, elements such as Co, Ni, Cr, Fe, Mo, and Ti in the substrate diffuse along the grain boundaries towards the coating, forming a distinct interdiffusion region with Cr and Ni in the coating, achieving a tight atomic-level bond between the coating and the substrate. High-resolution transmission electron microscopy confirms the existence of a coherent interface between the coating and the substrate, with parallel and equally spaced lattice fringes at the interface, no dislocation distribution, and low lattice mismatch. This structure significantly improves the interfacial separation work, effectively mitigating the thermal expansion mismatch effect between the two, which is the fundamental reason why the coating exhibits a high film-substrate adhesion of 89 N.

[0047] This invention provides the application of the high-temperature wear-resistant protective coating described above in the surface protection of GH6159 high-temperature alloy load-bearing bolts for aero-engines.

[0048] The following detailed description, in conjunction with embodiments, illustrates the high-temperature wear-resistant protective coating, its preparation method, and its application provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0049] Example 1 Step 1: Matrix Pretreatment 1) The base material is GH6159 high-temperature alloy, and the machining size is Φ16.5 mm × 8 mm. It is ground step by step using 80 mesh, 240 mesh, 400 mesh, 800 mesh, 1200 mesh, 2000 mesh and 3000 mesh SiC sandpaper, and finally polished to obtain a smooth and flat initial surface.

[0050] 2) Surface roughening was performed using a 900-type integrated chamber sandblasting machine. 80-mesh white corundum (Al2O3) was used as the sandblasting medium, with a sandblasting air pressure of 0.3 MPa. The spray gun was held perpendicular to the sample surface at a distance of approximately 10 cm, and the sandblasting time was 10 s to ensure uniform surface treatment. After sandblasting, the sample was ultrasonically cleaned with alcohol for 20 minutes to thoroughly remove any residual sand particles adhering to the surface. Surface roughness was measured using a laser confocal microscope (LSCM, OLS5000), and the maximum surface roughness (Sa) was controlled below 1.8 μm to meet the surface finish requirements for bolt-type fasteners.

[0051] Step 2: Magnetron sputtering co-deposition of CrAl and Ni thin films 1) Deposition was performed using a TGP500 multi-functional magnetron sputtering system. The target material selected was Al. 60 Cr 40Binary alloy targets (at.%) and pure Ni targets (purity ≥99.95%) were used, with target dimensions of Φ76.2 mm × 3 mm. The pretreated substrate was fixed on the sample stage, with the target surface 80 mm away from the sample surface.

[0052] 2) Evacuate to a background vacuum level ≤ 5 × 10⁻⁶ -5 Pa, turn on the heating system, and set the deposition temperature to 370℃. Introduce high-purity argon gas (Ar, purity ≥99.99%) as the working gas and adjust the chamber pressure to 0.6 Pa. Set Al 60 Cr 40 The target sputtering power was 100 W, the Ni target sputtering power was 50 W, the bias voltage was set to -100 V, and the pulse duty cycle was 60%. The sample stage rotation motor was started, the rotation speed was set to 5 r / min, and the deposition time was 360 min. After deposition, the gas cylinder, gas valve, heating system, and sample stage rotation were turned off. The sample was removed after the chamber temperature dropped below 30℃, yielding an Al-Cr-Ni co-deposited layer with a thickness of approximately 2.6 μm. EDS energy dispersive spectroscopy analysis showed that the coating composition was approximately: Al 23.05 at.%, Cr 30.23 at.%, Ni 46.72 at.%.

[0053] Step 3: Ion nitriding treatment The sample with the deposited Al-Cr-Ni metallic coating was placed in an LDMC-30AZ pulsed ion nitriding furnace, positioned on the cathode plate, and the furnace chamber was sealed. The vacuum system was activated to evacuate the furnace to below 15 Pa. High-purity ammonia (NH3 ≥ 99.99%) and high-purity argon (Ar ≥ 99.99%) were introduced as the nitriding atmosphere and protective gas, with a mixing ratio of NH3:Ar = 5:1 and a total gas flow rate of 0.6 L / min. The heating and glow discharge power supplies were turned on, and the process parameters were set as follows: temperature 500℃, time 10 h, final stable pressure 220 Pa, glow discharge voltage 680 V, and duty cycle 40%–60%. Throughout the nitriding process, the glow discharge status was observed in real-time through the equipment window, and current changes were monitored to ensure the peak current remained between 3 and 5 A. During the nitriding process, high-energy particles continuously bombard the sample surface. Al atoms, due to their lighter mass, are selectively sputtered and stripped, forming Al-deficient regions. At the same time, N atoms gradually penetrate from the surface to the deeper layers, and Ni atoms diffuse into the low-nitrogen potential region (bottom of the coating), inducing the formation of a multilayer structure with gradient characteristics of "decreasing N content, increasing Ni content, and decreasing grain size".

[0054] Step 4: Cooling After the nitriding process is complete, close the gas cylinder and valve control switch, start the vacuum pump to evacuate to below 15 Pa, and close the vacuum valve and control system to prevent the sample from oxidizing at high temperatures. Keep the cooling water circulating, and after the furnace cools to room temperature, open the chamber and remove the sample.

[0055] The sample number prepared in this embodiment is: GH6159+MS+PN (100 W Al) 60 Cr 40 + 50 W Ni + PN). Performance testing showed that this sample exhibited the best overall performance: nanohardness 26.47 GPa, film-substrate adhesion 87.9 N, and room temperature wear rate 1.18 × 10⁻⁶. -6 mm 3 / Nm, 800℃ high-temperature wear rate 0.542×10 -6 mm 3 / Nm.

[0056] Example 2 Step 1: Matrix Pretreatment The substrate pretreatment process is exactly the same as in Example 1, including stepwise grinding, polishing, sandblasting (0.3 MPa, 10 s) and ultrasonic cleaning with alcohol (20 min), with the surface roughness Sa ≤ 1.8 μm.

[0057] Step 2: Magnetron sputtering co-deposition of CrAl and Ni thin films The same magnetron sputtering equipment and parameters as in Example 1 were used, the difference being that the Ni target power was set to 30 W. Specific parameters were: background vacuum ≤ 5 × 10⁻⁶ W. -5 Pa, working gas Ar, pressure 0.6 Pa, deposition temperature 370℃, Al 60 Cr 40 The target power was 100 W, the Ni target power was 30 W, the bias voltage was -100 V, the duty cycle was 60%, the stage rotation speed was 5 r / min, and the deposition time was 360 min. After deposition, the furnace was slowly cooled to room temperature to obtain an Al-Cr-Ni co-deposited layer with a thickness of approximately 2.6 μm.

[0058] Step 3: Ion nitriding treatment The ion nitriding process is exactly the same as in Example 1: atmosphere NH3:Ar=5:1, total flow rate 0.6 L / min, temperature 500℃, time 10 h, gas pressure 220 Pa, glow voltage 680 V, duty cycle 40%~60%.

[0059] Step 4: Cooling The cooling process is exactly the same as in Example 1: the glow discharge is turned off, the vacuum is evacuated to below 15 Pa, and the furnace is cooled to room temperature.

[0060] The sample number prepared in this embodiment is: GH6159+MS+PN-2 (100 W Al) 60 Cr 40 + 30 W Ni + PN).

[0061] Example 3 Step 1: Matrix Pretreatment The substrate pretreatment process is exactly the same as in Example 1, including stepwise grinding, polishing, sandblasting (0.3 MPa, 10 s) and ultrasonic cleaning with alcohol (20 min), with the surface roughness Sa ≤ 1.8 μm.

[0062] Step 2: Magnetron sputtering co-deposition of CrAl and Ni thin films The same magnetron sputtering equipment and parameters as in Example 1 were used, the difference being that the Ni target power was set to 80 W. Specific parameters were: background vacuum ≤ 5 × 10⁻⁶ W. -5 Pa, working gas Ar, pressure 0.6 Pa, deposition temperature 370℃, Al 60 Cr 40 The target power was 100 W, the Ni target power was 80 W, the bias voltage was -100 V, the duty cycle was 60%, the stage rotation speed was 5 r / min, and the deposition time was 360 min. After deposition, the furnace was slowly cooled to room temperature to obtain an Al-Cr-Ni co-deposited layer with a thickness of approximately 2.6 μm.

[0063] Step 3: Ion nitriding treatment The ion nitriding process is exactly the same as in Example 1: atmosphere NH3:Ar=5:1, total flow rate 0.6 L / min, temperature 500℃, time 10 h, gas pressure 220 Pa, glow voltage 680 V, duty cycle 40%~60%.

[0064] Step 4: Cooling The cooling process is exactly the same as in Example 1: the glow discharge is turned off, the vacuum is evacuated to below 15 Pa, and the furnace is cooled to room temperature.

[0065] The sample number prepared in this embodiment is: GH6159+MS+PN-3 (100 W Al) 60 Cr 40 + 80 W Ni + PN).

[0066] Example 4 Step 1: Matrix Pretreatment The substrate pretreatment process is exactly the same as in Example 1, including stepwise grinding, polishing, sandblasting (0.3 MPa, 10 s) and ultrasonic cleaning with alcohol (20 min), with the surface roughness Sa ≤ 1.8 μm.

[0067] Step 2: Magnetron sputtering co-deposition of CrAl and Ni thin films The same magnetron sputtering equipment and parameters as in Example 1 were used, except that the Ni target power was set to 100 W. Specific parameters were: background vacuum ≤ 5 × 10⁻⁶ W. -5Pa, working gas Ar, pressure 0.6 Pa, deposition temperature 370℃, Al 60 Cr 40 The target power was 100 W, the Ni target power was 100 W, the bias voltage was -100 V, the duty cycle was 60%, the stage rotation speed was 5 r / min, and the deposition time was 360 min. After deposition, the furnace was slowly cooled to room temperature to obtain an Al-Cr-Ni co-deposited layer with a thickness of approximately 2.6 μm.

[0068] Step 3: Ion nitriding treatment The ion nitriding process is exactly the same as in Example 1: atmosphere NH3:Ar=5:1, total flow rate 0.6 L / min, temperature 500℃, time 10 h, gas pressure 220 Pa, glow voltage 680 V, duty cycle 40%~60%.

[0069] Step 4: Cooling The cooling process is exactly the same as in Example 1: the glow discharge is turned off, the vacuum is evacuated to below 15 Pa, and the furnace is cooled to room temperature.

[0070] The sample number prepared in this embodiment is: GH6159+MS+PN-4 (100 W Al) 60 Cr 40 + 100 W Ni +PN).

[0071] Comparative Example 1 Blank control group (unmodified matrix): The high-temperature alloy matrix was polished without any surface modification and served as a blank control sample, numbered GH6159.

[0072] Comparative Examples 2-6 Single magnetron sputtering metal coating sample: The GH6159 substrate was first pretreated by sandblasting, and then an Al-Cr-Ni metal coating was deposited using magnetron sputtering (MS). The same magnetron sputtering equipment and parameters as in Example 1 were used, the difference being the Ni target power. This group of samples fixed Al 60 Cr 40 With the target sputtering power constant, five groups of samples with different Ni contents were prepared by adjusting the Ni target power (0, 30, 50, 80, 100 W). The specific numbers are as follows: 100 W Al 60 Cr 40 +0 WNi (GH6159+MS-1, as Comparative Example 2), 100 W Al 60 Cr 40 +30 W Ni (GH6159+MS-2, as Comparative Example 3), 100 W Al 60 Cr 40+50 W Ni (GH6159+MS, as Comparative Example 4), 100 W Al 60 Cr 40 +80 W Ni (GH6159+MS-3, as Comparative Example 5), 100 W Al 60 Cr 40 +100 W Ni (GH6159+MS-4, as Comparative Example 6).

[0073] Comparative Example 7 Single plasma nitriding sample: Only the polished GH6159 substrate was subjected to plasma nitriding (PN) treatment, without depositing any coating. The plasma nitriding process was exactly the same as in Example 1, and the sample was numbered GH6159+PN.

[0074] Comparative Example 8 The only difference from Example 1 is that the Ni target power was 0 W during magnetron sputtering. The prepared sample was numbered: GH6159+MS+PN-1 (100 W Al 60 Cr 40 + 0 W Ni + PN).

[0075] Structural characterization and performance testing The cross-section of the GH6159+MS+PN sample was observed by scanning electron microscopy (SEM) and EDS surface scanning. The results are as follows: Figure 1 As shown. By Figure 1 The coating thickness is approximately 2.608 μm. The coating and substrate interface are tightly bonded, with no cracks, pores, or other defects, indicating good adhesion between the coating and the substrate. Combined with the corresponding EDS surface scan results, the coating forms five distinct structural regions from the surface to the core: Sublayer I is mainly enriched with Cr, Ni, N, and matrix elements such as Co, Fe, and Mo that diffuse to the coating surface at high temperatures, with a significant lack of Al; Sublayer II is a uniformly enriched region of Al, Cr, Ni, and N, constituting the main functional layer of the coating; Sublayer III is mainly enriched with Al and O; Sublayer IV is mainly enriched with Ni; and Sublayer V is enriched with Ni and a small amount of O.

[0076] The GH6159+MS+PN sample was characterized by XRD, and the results are shown in the figure. Figure 2 . Figure 2In the XRD pattern, diffraction peaks observed at diffraction angles 2θ≈37.6°, 43.7°, 63.5°, 76.2°, and 80.3° correspond to the (111), (200), (220), (311), and (222) crystal planes of the face-centered cubic Cr(Al)N structure, respectively. This phase is a substitutional solid solution phase formed by Al with smaller atomic radii substituting for Cr with larger atomic radii. The lattice distortion caused by the substitution increases the strain energy of the coating, thereby achieving solid solution strengthening. In addition, FeN was also detected in the XRD pattern. 0.0324 Diffraction peaks were observed for nitrides and intermetallic compounds such as Ni3Fe and AlNi3. Notably, no obvious diffraction peaks were observed for wt-AlN or elemental Al with a close-packed hexagonal structure within the XRD detection limit, indicating that Al was fully dissolved into the CrN lattice.

[0077] To characterize the cross-sectional microstructure of the coating in detail, transmission electron microscopy (TEM) was used to observe the GH6159+MS+PN sample. The results are shown in Figure 3, including bright-field images, selected area electron diffraction (SAED) patterns, and high-resolution images. Figure 3 In the middle, (a) is Figure 1 A magnified image and EDS plot of the first layer region show a twinning morphology at position b. Combined with EDS energy dispersive spectroscopy analysis, the twinning region is enriched in Ni, Fe, and contains a small amount of Co. Further analysis using high-resolution images (…) Figure 3 Analysis of (b) and the corresponding selected area electron diffraction (c) confirmed that the main phase corresponding to the twin was Ni3Fe. Figure 3 Selected area electron diffraction analysis was performed on region d in (a) (see) Figure 3 (d) indicates that CrN and FeN coexist at this location. 0.0324 Phase composition. Notably, after ion nitriding treatment, a significant loss of Al element was observed in this layer. In summary, the first layer of the coating mainly consists of Ni3Fe, CrN, and FeN. 0.0324 It is composed of equal phases.

[0078] Figure 3 (e) is Figure 1 A bright-field TEM image of the second layer region shows a significant gradient structure along the growth direction: the top columnar crystals are approximately 180 nm wide, while the bottom crystals are thinner to approximately 50 nm. SAED analysis of this region (see...) Figure 3 (f,g)), the diffraction ring markings indicate that the main phases of this layer are Cr(Al)N and elemental Ni, while the SAED diffraction rings in the bottom region of the coating (see...) Figure 3 The better continuity in the middle (g) region indicates finer grains, further demonstrating that the main working layer (second layer) of the coating exhibits a gradient structure with coarser grains at the top and finer grains at the bottom. High-resolution analysis of the middle part of the coating (see...) Figure 3 In the magnified image (h), the Fast Fourier Transform (FFT) diffraction pattern identification shows a face-centered cubic Cr(Al)N phase. In the lower right region of the magnified image (h), as shown in (i), two sets of clear lattice fringes can be observed, with measured spacings of 0.237 nm and 0.206 nm, corresponding to the (111) and (200) crystal planes of the Cr(Al)N phase. These measured values ​​are slightly smaller than the corresponding interplanar spacing of the standard CrN phase (PDF#76-2494), attributed to the partial substitution of Cr atoms by smaller Al atoms, leading to lattice contraction. Figure 3 Inverse Fourier transform of medium- and high-resolution images (h) is performed as follows: Figure 3 As shown in (j), it can be seen that a large number of dislocations are uniformly distributed in the II sublayer of the coating, which can improve the hardness and strength of the coating.

[0079] right Figure 1 Magnified observations were performed on the sublayers III, IV, and V shown (see...). Figure 4 In the middle (a), high-resolution analysis was performed, focusing on layer III (see...). Figure 4 (b) Figure 4 The middle (ce) are respectively Figure 4 Enlarged images of the corresponding regions in (b): Region c has a measured interplanar spacing of 0.237 nm, corresponding to the (111) crystal plane of Cr(Al)N; Region d has an interplanar spacing of 0.204 nm, corresponding to the (111) crystal plane of elemental Ni. Combined with... Figure 1 The EDS elemental distribution results show that this layer is enriched in Al and O. Further analysis using high-resolution images and selected area electron diffraction (see...) Figure 4 In (e) it was found that the atoms in this region were arranged in a disordered state, and its FFT spectrum showed typical diffuse halo characteristics, indicating the presence of an amorphous phase. Based on the above results, it is speculated that layer III is a composite structure composed of amorphous Al2O3 encapsulating Cr(Al)N and Ni nanocrystals.

[0080] right Figure 4 Electron diffraction analysis was performed on region f in (a) (see) Figure 4 (f) The results show that the region is mainly c-Ni. Combined with the EDS results, it can be seen that the fourth layer is elemental nickel, and the fifth layer is based on elemental nickel, with a small amount of solid solution from matrix elements such as Co, Cr, Fe, Mo, Ti and other elements. Figure 4 Image (g) is a high-resolution image of the interface between the fifth layer and the substrate. A magnified view of region h (see image (h) in section 4) reveals a set of parallel and equally spaced lattice fringes in both the coating and substrate, indicating a coherent interface. This coherent structure significantly improves the interfacial separation work, which is beneficial for enhancing the film-substrate bonding strength. Furthermore, Figure 4 The IFFT corresponding to (h) in the middle (see) Figure 4 (i) shows that there is no dislocation distribution at the interface between the coating and the substrate, further confirming the low lattice mismatch and good interfacial coherence.

[0081] Hardness and toughness were tested on samples from some of the embodiments and comparative examples. The test method was as follows: a nanoindenter was used, and the maximum indentation of the sample was controlled within 260 nm in continuous stiffness measurement mode. The nanohardness (H) and Young's modulus (E) of the sample were measured, and H / E and H were calculated. 3 / E 2 The ratio of these values ​​is used to characterize the toughness of the coating. The test results are shown in Table 1.

[0082] In extreme environments, coatings with high hardness and toughness must also possess excellent film-substrate adhesion to improve component lifespan and operational efficiency; otherwise, premature coating peeling and failure are likely. This invention employs a scratch test to assess film-substrate adhesion. During the experiment, the indenter generates a linear scratch trajectory of 6 mm in length at a speed of 1 mm / min, while the normal load linearly increases from 0 N to 130 N. To reduce random errors, all scratch tests are repeated at least three times, and the average value is taken.

[0083] Figure 5 The bonding strength test results are for GH6159+MS(a) and GH6159+MS+PN(b) samples. Figure 5 As shown, for the GH6159+MS sample, the frictional force increases linearly with displacement when the scratch distance is less than 2.492 mm; after exceeding this distance, the curve shows a clear inflection point and the fluctuation intensifies, indicating that the substrate has been exposed under a load of approximately 53.99 N. Therefore, the film-substrate adhesion of this sample is approximately 53.99 N. Similarly, the film-substrate adhesion of the GH6159+MS+PN sample is approximately 87.90 N, which is significantly higher than the former. The enhanced adhesion is mainly attributed to the higher treatment temperature and the thermal activation effect of nitrogen ions during nitriding, which promotes strong interdiffusion between the surface coating elements and the internal substrate elements, thereby achieving metallurgical bonding and effectively improving the interfacial bonding strength. The film-substrate adhesion of each sample is summarized in Table 1.

[0084] Table 1. Membrane-substrate adhesion, hardness, and toughness

[0085] Table 1 shows that the hardness and toughness of the GH6159+MS+PN sample are significantly higher than those of other samples, proving that the plating-nitriding composite process can achieve a synergistic improvement in both hardness and toughness. Simultaneously, the Al-Cr-Ni metal coating on the sample surface exhibits greatly improved film-substrate adhesion after plasma nitriding treatment. In conclusion, when Al... 60 Cr 40When the sputtering power of the target is 100W and the Ni target power is 50W, plasma nitriding treatment can synergistically improve the hardness, toughness and film-substrate adhesion of the composite coating, greatly improve the mechanical properties, and lay a good foundation for its excellent tribological properties.

[0086] Comparing the above comparative examples with the embodiments, Tables 2 and 3 list the key tribological performance parameters of 12 groups of samples with different treatment processes after 1 hour of wear at room temperature and high temperature (800℃), mainly including the average coefficient of friction, wear depth, and wear rate. The specific test methods are as follows: Rotary friction and wear tests were conducted on each sample using a pin-disc type multi-functional friction and wear testing machine (MFT-5000) at both room temperature (25℃) and high temperature (800℃). Si3N4 balls with a hardness of 1600 HV and a diameter of 9.525 mm were selected as the friction pair. The applied load, friction radius, rotational speed, and friction duration were 20 N, 4 mm, 300 r / min, and 3600 s, respectively. Each experiment was performed at least five times, and the average value was taken to ensure the repeatability of the experimental data.

[0087] Wear marks on the samples after wear testing were observed using a laser confocal microscope (LEXT-3D, OLS5000, Nishi-Shinjuku, Japan). For each sample, the cross-sectional area was measured at five randomly selected locations on the wear mark, and the average value was calculated. The average cross-sectional area S of the wear mark was substituted into the following formula to calculate the wear volume and wear rate of the sample: Formula 1; Formula 2; Where: V is the wear volume (mm) 3 ); r is the wear mark radius (mm); W r For wear rate (10 -6 mm 3 / Nm); F is the applied load (N); L is the total sliding distance (m).

[0088] Figure 6Tribological properties of GH6159 matrix, GH6159+MS, GH6159+PN, and GH6159+MS+PN samples at room temperature are shown in the figures. (a1) GH6159 matrix, (b1) GH6159+MS, (c1) GH6159+PN, (d1) GH6159+MS+PN. The three-dimensional morphology of the worn surface observed by laser confocal microscopy is shown in the figures. (a2) GH6159 matrix, (b2) GH6159+MS, (c2) GH6159+PN, (d2) GH6159+MS+PN. The wear track profile curves and corresponding wear volume and wear rate are shown in the figures. (a3) ​​GH6159 matrix, (b3) GH6159+MS, (c3) GH6159+PN, (d3) GH6159+MS+PN.

[0089] Table 2. Room temperature wear data for each sample

[0090] Depend on Figure 6 As shown in Table 2, the average friction coefficient of the blank control group (GH6159) was 0.7516±0.0392, and the wear depth was (35.52±3.25)×10. -3 mm, wear rate (93.16±3.67)×10 -6 mm 3 / Nm indicates that the wear resistance of the high-temperature alloy matrix without surface strengthening treatment is poor.

[0091] Compared with the substrate, the friction coefficient, wear depth, and wear rate of the magnetron sputtered metal coating samples (GH6159+MS, GH6159+MS-1, GH6159+MS-2, GH6159+MS-3, GH6159+MS-4) did not show significant improvement. This indicates that simply depositing an Al-Cr-Ni metal coating by magnetron sputtering, regardless of the Ni content, cannot effectively improve the tribological properties of the samples. Only the plasma nitriding sample (GH6159+PN) showed a slightly higher average friction coefficient than the substrate, but the wear depth and wear rate both decreased significantly, resulting in a significant improvement in wear resistance. This demonstrates that plasma nitriding treatment can effectively enhance the wear resistance of the substrate.

[0092] For the plating-diffusion composite modified samples (GH6159+MS+PN series), the average friction coefficient of each sample fluctuated relatively little with the gradient change of Ni target power, but the wear depth and wear rate showed significant fluctuations. A comprehensive comparison of the performance parameters of all samples showed that when the Ni target power was 50W, the sample (GH6159+MS+PN) exhibited the best tribological performance: the average friction coefficient decreased to 0.6609±0.0328, and the wear depth and wear rate decreased significantly to (1.85±0.51)×10⁻⁶. - 3 mm, (1.18±0.20)×10 -6 mm 3 / Nm.

[0093] Compared with the GH6159 substrate, the three performance parameters of the GH6159+MS+PN sample decreased by 12.07%, 94.79%, and 98.73%, respectively. This result fully demonstrates that the plating-infiltration composite coating can significantly reduce material wear and improve the wear resistance of the coating while moderately reducing the friction coefficient of the sample, thus achieving effective protection for the GH6159 high-temperature alloy.

[0094] Figure 7 Tribological properties of GH6159 matrix, GH6159+MS, GH6159+PN, and GH6159+MS+PN samples at high temperature are shown in the following figures: (a1) GH6159 matrix, (b1) GH6159+MS, (c1) GH6159+PN, (d1) GH6159+MS+PN; three-dimensional morphology of the worn surface observed by laser confocal microscopy: (a2) GH6159 matrix, (b2) GH6159+MS, (c2) GH6159+PN, (d2) GH6159+MS+PN; wear track profile curves and corresponding wear volume and wear rate: (a3) ​​GH6159 matrix, (b3) GH6159+MS, (c3) GH6159+PN, (d3) GH6159+MS+PN.

[0095] Table 3 High-temperature wear data for various types of samples

[0096] Depend on Figure 7 As shown in Table 3, compared with the room temperature test, the break-in period of all samples was significantly shorter at high temperature, the average friction coefficient decreased and the fluctuation was reduced, and the wear rate also decreased significantly.

[0097] Specifically, the average coefficient of friction and wear rate of the GH6159 alloy matrix are 0.3764 and 6.848 × 10⁻⁶, respectively. - 6 mm3 / N·m, its three-dimensional wear morphology ( Figure 7 (a2) shows a large number of furrows on the surface, indicating severe abrasive wear; the average friction coefficient and wear rate of the GH6159+MS sample are 0.3231 and 6.394×10, respectively. -6 mm 3 / N·m, the coefficient of friction is reduced, but the improvement in wear resistance is limited. Severe abrasive wear still exists, and a large amount of wear debris accumulates around the wear tracks (see Figure 7 (b2) This is due to the low adhesion and hardness of the magnetron sputtered Al-Cr-Ni metal film, which makes it easy to peel off from the substrate and accumulate; the average friction coefficient and wear rate of the GH6159+PN sample were 0.4341 and 3.693×10, respectively. -6 mm 3 / N·m, where the coefficient of friction is slightly higher than that of the matrix, while the wear rate is significantly reduced. This is due to the hard nitride formed on the surface during nitriding, which improves the sample's resistance to abrasive wear. This is evident from its smoother wear track morphology compared to the worn matrix (see Figure 7 As can be seen from (c2), the GH6159+MS+PN sample exhibits the best high-temperature tribological properties, with an average friction coefficient of 0.2968 and a wear rate of 0.542×10⁻⁶. -6 mm 3 / N·m, respectively, decreased by approximately 21.1% and 92.1% compared to the matrix. From its three-dimensional wear morphology (see... Figure 7 (d2) It can be seen that the surface of the wear mark becomes smooth and flat, with no wear debris accumulation.

[0098] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-temperature wear-resistant protective coating, characterized in that, The Al-Cr-Ni metal layer was first deposited on the surface of a GH6159 alloy substrate by magnetron sputtering, followed by plasma nitriding. From the surface inwards, the high-temperature wear-resistant protective coating sequentially comprises layer I, layer II, layer III, layer IV, and layer V; layer I is composed of CrN, Ni3Fe, and FeN. 0.0324 Phase composition; The second layer comprises Cr(Al)N and elemental Ni phase, and exhibits a gradient characteristic along the depth direction, with decreasing N content, increasing Ni content, and decreasing grain size. The third layer is an amorphous composite layer, comprising amorphous Al2O3 encapsulating Cr(Al)N and Ni nanocrystals; The IV layer is mainly composed of elemental Ni; The V layer forms a coherent interface with the GH6159 matrix.

2. The high-temperature wear-resistant protective coating according to claim 1, characterized in that, In the second layer, the upper layer is a coarse Cr(Al)N columnar crystal, and the lower layer is a composite structure in which Ni phase encapsulates Cr(Al)N nanocrystals.

3. The high-temperature wear-resistant protective coating according to claim 1, characterized in that, The high-temperature wear-resistant protective coating is metallurgically bonded to the GH6159 substrate, with a film-substrate adhesion strength ≥87.9 N.

4. The high-temperature wear-resistant protective coating according to claim 1, characterized in that, The hardness of the high-temperature wear-resistant protective coating is above 25 GPa.

5. The method for preparing the high-temperature wear-resistant protective coating according to any one of claims 1 to 4, characterized in that, Includes the following steps: An Al-Cr-Ni metal coating was deposited on the surface of a GH6159 alloy substrate by magnetron sputtering, resulting in a substrate with the Al-Cr-Ni metal coating deposited on it. The conditions for magnetron sputtering include: Al 60 Cr 40 Target power 80~100 W, Ni target power >0 and ≤100 W, deposition temperature 300~370℃, bias voltage -50~-100 V, deposition time 5~10 h; The substrate with the deposited Al-Cr-Ni metal coating is subjected to plasma nitriding treatment to form layers I, II, III, IV and V in situ, thereby obtaining the high-temperature wear-resistant protective coating; The conditions for plasma nitriding treatment include: temperature 400~500℃, time 8~10 h, gas pressure 200~220 Pa, and atmosphere of NH3 or NH3-Ar mixed atmosphere.

6. The preparation method according to claim 5, characterized in that, The Ni target power for the magnetron sputtering is 50 W.

7. The preparation method according to claim 5, characterized in that, The flow ratio of NH3 to Ar in the NH3-Ar mixed atmosphere is 4:1 to 5:

1.

8. The preparation method according to claim 5, characterized in that, The magnetron sputtering process uses a gas pressure of 0.4–0.6 Pa, a duty cycle of 40–60%, a stage rotation speed of 2–5 r / min, and a target-substrate distance of 60–80 mm.

9. The preparation method according to claim 5, characterized in that, The plasma nitriding treatment uses a glow discharge power supply with a glow discharge voltage of 680~720 V, a duty cycle of 40~60%, and a peak current maintained at 3~5 A.

10. The application of the high-temperature wear-resistant protective coating according to any one of claims 1 to 4 or the high-temperature wear-resistant protective coating prepared by the preparation method according to any one of claims 5 to 9 in the surface protection of GH6159 high-temperature alloy load-bearing bolts for aero-engines.

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