TiNx skeleton structure reinforced high-wear-resistance amorphous composite coating and preparation method thereof

Abstract

The invention discloses a TiNx skeleton structure reinforced high-wear-resistance amorphous composite coating and a preparation method thereof. Belongs to the technical field of functional protection materials and surface engineering. The composite coating is composed of a Fe-based amorphous matrix and a TiNx skeleton phase, the TiNx phase is distributed in the coating in a three-dimensional penetrating form, and the TiNx phase and the Fe-based amorphous matrix form a continuous metallurgical bonding structure. According to the framework structure, the interface bonding strength and the crack resistance of the coating are remarkably improved, and the problems of brittle fracture and oxidative wear of a traditional amorphous coating in the frictional wear process are effectively inhibited. Compared with a traditional physical powder mixing method and a thermal spraying method needing to introduce a metal bonding layer, the method has the advantages that the double effects of high adhesive force without the bonding layer and self-supporting framework structure strengthening are achieved through a powder self-construction mechanism, the process is simplified, and the structure is stable. The coating has the characteristics of high hardness, low friction coefficient and excellent wear resistance, and has good engineering adaptability and popularization value.

Description

Technical Field

[0001] This invention relates to a highly wear-resistant coating, and more particularly to an Fe-based amorphous composite coating reinforced by a TiNx framework structure, and especially to a highly wear-resistant amorphous composite coating reinforced by a TiNx framework structure and its preparation method. It belongs to the field of functional protective materials and surface engineering technology. Background Technology

[0002] During the service life of mechanical components, friction and wear are common phenomena caused by the relative movement between contact surfaces. Friction and wear lead to the migration and peeling of surface materials, causing degradation of the surface morphology and dimensions of the workpiece, thereby reducing its working performance and service reliability.

[0003] Fe-based amorphous coatings are widely used in protective coatings due to their high strength, high hardness, and excellent corrosion resistance. They exhibit a low coefficient of friction and wear rate under dry friction conditions, and their wear resistance is significantly superior to traditional materials such as low-carbon steel, stainless steel, and alumina. However, Fe-based amorphous coatings have inherent defects such as high brittleness, low toughness, and sensitivity to oxidation, often exhibiting a failure mode where fatigue wear and oxidative wear coexist. Studies have shown that the wear rate and oxidation reaction of this type of coating are highly sensitive to the sliding rate. Under high-speed friction conditions, the temperature rise at the friction interface leads to rapid thickening of the oxide layer. Due to the high brittleness of the oxide layer and the accumulation of residual stress, it is prone to local cracking and peeling. The secondary abrasion of the detached debris further exacerbates coating loss.

[0004] Furthermore, stress cracks generated during friction often propagate along the layered oxide interface. Due to the lack of plastic buffering capacity in Fe-based amorphous materials, cracks easily initiate at interface defects or pores and propagate rapidly along the layered interface, ultimately leading to interlayer delamination and spalling. These problems severely limit the application of Fe-based amorphous coatings in high-load wear-resistant applications.

[0005] Currently, developing second-phase reinforced Fe-based amorphous composite coatings is considered an effective way to alleviate this problem. By introducing ceramic or intermetallic compound phases, the continuous amorphous structure can be broken, hindering crack propagation and reducing oxidation sensitivity. However, most existing composite coatings are dispersed phase structures, resulting in limited reinforcement effects. This invention proposes a TiNx skeleton-reinforced amorphous composite coating, which achieves in-situ formation of the TiNx skeleton through reactive plasma spraying and is filled with an Fe-based amorphous phase. This significantly improves the crack resistance and wear resistance while ensuring the coating's density and corrosion resistance. A literature search revealed no technical reports with the same inventive solution as this invention. Summary of the Invention

[0006] This invention provides an Fe-based amorphous composite coating that constructs a TiNx phase framework in situ via reactive plasma spraying. This coating exhibits high hardness, high bonding strength, and excellent wear resistance. Unlike traditional simple powder mixing or layered spraying, this invention is based on the concept of self-architectured microstructure. Through the non-uniform reaction path induced by powder particle size differences and the in-situ nitriding reaction mechanism, a TiNx framework network with continuous connectivity is spontaneously formed during the spraying process, thereby significantly improving the overall performance of the coating.

[0007] Meanwhile, this invention provides a method for preparing a highly wear-resistant amorphous composite coating reinforced with a TiNx skeleton structure.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: Design and preparation of composite spraying powder:

[0009] This invention uses FeCrMo-based amorphous precursor powder and high-purity Ti powder as raw materials to construct a system with dual differences in morphology and particle size, so as to realize a composite powder with a reaction-self-constructed TiNx framework.

[0010] The FeCrMo-based amorphous precursor powder has a particle size range of 54-120 μm, with an approximately spherical morphology, smooth surface, and good flowability. The Ti powder has a particle size range of 10-25 μm, with an irregular morphology, rough surface, and high activity. Due to the significant differences in particle size and morphology between the two powders, the Ti powder can be selectively adsorbed and embedded on the surface of the amorphous powder under high-energy ball milling. Furthermore, the Ti powder coverage on the surface of the composite powder is not less than 80%, forming an "amorphous core-Ti shell" coating structure, thereby providing a uniform and continuous Ti distribution for subsequent reactions.

[0011] In the preparation process, Fe-based amorphous alloy powder (i.e., FeCrMo-based amorphous powder) and Ti powder are mixed at a mass ratio of 5 wt.%–30 wt.%, preferably 10 wt.%–20 wt.%; more preferably, Ti:FeCrMo amorphous = 10:90 or 20:80. After the FeCrMo amorphous powder and Ti powder are mixed at the mass ratio, they are placed in a high-energy ball mill for mechanical mixing and coating. The ball milling time is controlled at 4–6 h, and the rotation speed is 200–250 rpm. To improve the coating stability, 0.5–1 wt.% of polyvinyl alcohol-based organic surfactant is added to the mixed powder during the ball milling process to slow down cold welding and agglomeration, and to enhance the adhesion of Ti powder to the surface of the amorphous powder.

[0012] After ball milling, the resulting composite powder is dried in an oven at 80-110 °C for 2-3 hours to remove adsorbed moisture and organic residues. After drying, the powder is sieved through a 100-mesh sieve to remove agglomerated particles, resulting in a composite spray powder with a concentrated particle size distribution and good flowability.

[0013] Preparation of TiNx / Fe-based amorphous composite coatings by reactive plasma spraying:

[0014] The prepared composite powder was used as a spraying material and deposited using a plasma spraying device with a current of not less than 600 A, with the power adjustable between 25-40 kW. The centerline temperature of the plasma flame was approximately 9000-13000 K, and the radial temperature gradient could reach 4000-8000 K (specifically, the temperature drop from the flame center to a certain radial position (e.g., 3–10 mm) was between 4000-8000 K, meaning that within a radial range of 3-10 mm, the temperature rapidly decreased along the radius, with a temperature difference of 4000-8000 K from the center to the edge), forming a dual gradient field of temperature and reaction within a spray distance of 80-120 mm. The working gas and the reactant gas are Ar / N2 mixtures, with the volume fraction of N2 controlled at 40%–70% (preferably 50%–60%), and the N2 flow rate maintained at 60 psi to provide a sufficient nitrogen source. During the TiNx phase spraying process, the powder feeding temperature is controlled to be stable within ±200 ℃ to ensure that the coating structure is uniformly fused during the melting process and to promote the in-situ reaction of Ti powder and nitrogen to generate the TiNx skeleton.

[0015] During the spraying process, the Ti layer coating the surface of the amorphous powder undergoes an in-situ reaction in a high-temperature N2 atmosphere, generating a TiNx phase (x≈0.3-1.1). Due to the irregular initial morphology of the Ti powder, the reaction of the coating layer is more uniform during the in-flight heating stage, and necking connections easily form between particles, thus forming an interconnected TiNx network structure on the particle surface. This network is inherited and extended during powder melting and rapid solidification, ultimately constructing a three-dimensional continuous framework in the coating.

[0016] In the post-coating stage, the amorphous substrate rapidly freezes to form an amorphous structure, while the TiNx framework structure is uniformly distributed and locally penetrates into the substrate surface, forming a micro-metallurgical bonding zone, thus achieving a strong interfacial bond between the coating and the substrate.

[0017] Coating microstructure evolution and interfacial bonding mechanism:

[0018] In the reactive spraying system of this invention, the in-situ autoconstruction of the TiNx skeleton is induced by the difference in powder morphology, and its formation process can be divided into three stages: In-situ reaction stage: The Ti coating layer reacts with N in a high-temperature plasma nitriding atmosphere to generate TiNx nanocrystals; Interface reconstruction stage: Diffusion reaction bands are formed between TiNx and the amorphous matrix, realizing the synergistic effect of metallurgical bonding and mechanical interlocking; The self-construction stage of the framework: The TiNx phase gradually connects during the deposition of multi-layer particles, forming a three-dimensional continuous network framework structure.

[0019] This framework phase can effectively release stress during coating cooling, inhibiting crack initiation and propagation, thereby significantly improving the overall toughness and structural stability of the coating. By controlling the coating thickness, reactive gas flow rate, and spraying temperature gradient, uniform matching between the TiNx framework and the amorphous matrix can be achieved.

[0020] In addition, by using sandblasting to roughen the substrate surface, a micro-recessed structure can be formed before spraying. The coating melt fully penetrates into the recessed area during deposition, thereby enhancing the synergistic effect of mechanical interlocking and metallurgical bonding, and achieving excellent adhesion performance without the need for traditional metal adhesive layers.

[0021] Performance verification:

[0022] Comparative experiments have verified that the TiNx / Fe-based amorphous composite coating prepared in this invention exhibits the following advantages: Excellent wear resistance: The wear coefficient and wear rate are significantly lower than those of Fe-based amorphous single-phase coating and dispersed TiNx-reinforced iron-based amorphous composite coating. The wear morphology is smooth with no obvious peeling. High density: The internal porosity of the coating is controlled below 4.2%, which is better than that of pure TiNx coating (8-10%). Significantly improved hardness: average microhardness reaches 1080 HV 0.2 The above represents an improvement of approximately 34% compared to Fe-based amorphous coatings; Significant improvement in toughness: The skeleton-matrix synergistic structure effectively inhibits brittle fracture and hinders crack propagation; Excellent oxidation resistance and thermal stability: The TiNx phase can suppress the propagation of cracks induced by high-temperature oxidation and improve the service stability of the coating in extreme environments.

[0023] In summary, by designing differences in powder particle size and morphology, this invention utilizes the self-assembly coating effect of irregular Ti powder and spherical amorphous powder to achieve in-situ self-construction of the TiNx skeleton and synergistic reinforcement of the amorphous matrix, thus obtaining a composite coating with high bonding strength, high hardness, and high corrosion and wear resistance without the need for a traditional adhesive layer.

[0024] The present invention provides an Fe-based amorphous composite coating reinforced by a TiNx framework structure, which has a friction coefficient of 0.39-0.42, a porosity of 3.9-4.2%, and a hardness of 1080-1115 HV. 0.2 The bonding strength is 28.48-29.32 MPa.

[0025] The present invention relates to the application of a TiNx skeleton-reinforced, wear-resistant amorphous composite coating in industrial components. These industrial components possess high hardness, high bonding strength, and corrosion and wear resistance. The industrial components include bearings, gears, pump shafts, valve seats, mining crushing components, mold cavities, rail transit brake discs, and high-wear components in marine engineering.

[0026] An industrial component is prepared using a TiNx skeleton-reinforced, highly wear-resistant amorphous composite coating according to the present invention.

[0027] The present invention has the following beneficial effects: I. Invention Concept and Innovation Traditional amorphous composite coatings often rely on physical mixing or multilayer stacking to achieve multiphase coexistence. However, this method suffers from problems such as interface weakening, phase delamination, and discontinuous framework, making it difficult to achieve true structural reinforcement. The innovative approach proposed in this invention is to induce in-situ reactions within the powder system during plasma spraying, allowing the reinforcing phases to spontaneously grow and interconnect within the amorphous matrix, thereby constructing a continuous framework structure. This "self-constructed" structure is not formed by external templates or mechanical stacking, but rather is the result of natural evolution through the inherent thermodynamic and kinetic processes of the material.

[0028] The formation of this in-situ skeleton depends on the coupled control of the following three key elements: 1. Gradient design of powder particle size and morphology.

[0029] This invention employs a composite design of near-spherical Fe-based amorphous alloy powder with a particle size of 54–120 μm and high-purity irregular Ti powder with a particle size of 10–25 μm to form a composite spraying powder system with morphology and particle size gradient. The Fe-based amorphous powder has a smooth surface and high sphericity, ensuring good flowability and spraying stability; while the Ti powder particles have a rough surface, with polyhedral angles and protrusions, resulting in a high specific surface area and endothermic activity.

[0030] After ball milling and compounding, Ti powder is distributed in the gaps and surface protrusions of the amorphous powder in a semi-coated and embedded manner. When the powder enters the plasma flame zone, a significant local heating gradient is formed due to the differences in thermal conductivity, particle size, and surface energy between the two types of powder. The smaller, coarser Ti powder absorbs heat more quickly in a short time, and the surface activation reaction occurs first; while the Fe-based amorphous powder provides heat buffer and flow channels in the form of a molten carrier.

[0031] This design introduces a gradient field in space for heating and reaction rates, enabling Ti powder to preferentially react with N in a high-temperature nitrogen atmosphere to generate the TiNx in-situ phase, laying the microscopic foundation for the subsequent formation of the framework network.

[0032] 2. Control of nitrogen reaction atmosphere and temperature field gradient.

[0033] During the spraying process, an N2-Ar mixture is used as both the working and reactive gas. The volume fraction of N2 is controlled at 40%–70% (preferably 50%–60%) to provide sufficient nitrogen source while maintaining arc stability. The spraying current is no less than 600 A, and the power adjustment range is between 25–40 kW. The plasma flame centerline temperature is approximately 9000–13000 K. Within a radial range of 3–10 mm, the temperature decreases radially, resulting in a temperature difference of 4000–8000 K from the flame center to the edge. A dual gradient field of temperature and reaction is formed within a spray distance of 80–120 mm.

[0034] In this environment, Ti particles coated on the surface of amorphous powder undergo a dynamic evolution of "partial nitriding - local melting - rapid solidification" during flight: Ti first reacts with nitrogen to form a nanoscale TiNx phase; subsequently, with the collision and cooling of the molten droplets, these TiNx nanoparticles agglomerate and connect along the droplet-gas interface, and finally construct a continuous three-dimensional framework TiNx reinforcement network in the amorphous matrix.

[0035] In addition, the difference in melting points between amorphous powder and Ti powder (approximately 300-400 °C) combined with the radial temperature difference of the flame causes TiNx to spontaneously grow in local enrichment areas and interweave with the amorphous matrix, forming a "skeleton-matrix" interpenetrating structure, thereby significantly improving the load-bearing capacity and crack resistance of the coating.

[0036] 3. Self-embedding bonding mechanism at the interface without adhesive layers.

[0037] To further improve the bonding performance of the coating-substrate interface, this invention performs hydrogen reduction activation treatment on the composite powder before spraying. The specific method is as follows: the powder is placed in a forming gas containing 5% H2 / 95% Ar and kept at 300-400 °C for 60 min to remove the surface oxide film and expose the active metal surface; then it is maintained in an inert or low-temperature nitrogen atmosphere (200-300 °C) for 30-60 min to introduce an active nitrogen adsorption layer on the powder surface.

[0038] This pretreatment allows for faster interfacial reactions during powder coating. When the high-temperature molten droplets come into contact with the sandblasted and roughened substrate surface, short-range diffusion and localized metallurgical reactions occur between the activated Fe-Ti-N elements, forming a dispersed transition reaction layer (approximately 2-5 μm thick). This region exhibits both mechanical interlocking and metallurgical bonding characteristics, achieving a high-adhesion structure that eliminates the need for traditional NiCrAl or Mo binder layers.

[0039] Experimental results show that this self-embedding bonding mechanism increases the interfacial bonding strength of the coating by approximately 40%-60% compared to traditional amorphous coatings, while reducing porosity to below 5%. Simultaneously, the presence of the framework structure effectively inhibits the propagation of interfacial microcracks, ensuring the integrity and durability of the coating under high loads and corrosive environments.

[0040] II. Organizational Evolution and Performance Mechanisms During the spraying process, as the droplets rapidly spread and solidify under high-speed impact, the TiNx phase preferentially grows and interconnects in the amorphous matrix, ultimately forming a continuous framework structure. This framework not only serves as a high-hardness phase reinforcement carrier, improving the overall hardness and rigidity of the coating, but also plays a role in crack deflection and energy dissipation at the microscopic level. Fracture morphology observation shows that the composite coating exhibits a distinctly rough and undulating structure, with cracks undergoing multiple deflections and passivation at the TiNx phase interface, forming a "serrated crack-resistant path," significantly improving the resistance to crack propagation.

[0041] Furthermore, the presence of the TiNx skeleton effectively limits the spread of oxidative wear. Fe-based amorphous coatings are prone to localized oxidation and peeling under dry sliding wear conditions, while the thermal stability and load dispersion of the continuous skeleton in the composite coating transforms its wear mechanism from initial oxidative wear to stable sliding wear. Experiments show that under a 10 N load and a 500 m wear distance, the coefficient of friction of the composite coating is approximately 0.42, significantly lower than the 0.48 of the Fe-based amorphous coating, resulting in a wear rate reduction of approximately 60%, and a significant decrease in both wear track width and depth.

[0042] Wear surface analysis further confirmed the strengthening effect of the skeleton. The Fe-based amorphous coating surface exhibited numerous furrows, microcracks, and oxide spalling zones, while the composite coating surface formed a dense, regular, scaly plastic deformation structure. This scaly structure is considered to be the result of adaptive deformation of the TiNx skeleton under the combined effects of frictional heat and shear stress; its continuous distribution can significantly reduce frictional resistance and prolong the stable wear stage.

[0043] III. Comparative Verification and Effect Description To verify the uniqueness of the in-situ framework mechanism of this invention, the following comparative samples were prepared: Comparative Example 1: Powder without high-energy ball milling activation treatment resulted in a coating with discrete TiNx distribution, no continuous skeleton formed, high porosity of 7.2%, and low bonding strength. Comparative Example 2: Using a conventional adhesive layer spraying process, although the density was slightly improved, the interface delamination was obvious and the skeleton structure was discontinuous. The sample of this invention forms a continuous TiNx framework through an activation-reaction-self-structure mechanism, with a porosity controlled below 4.2% and a microhardness of at least 1080 HV. 0.2The bonding strength is increased by more than 40%, and the wear resistance is significantly improved.

[0044] Therefore, the innovation of this invention lies in the in-situ self-design concept based on the difference between powder particle size and reaction kinetics. This method realizes the spontaneous interconnection and skeletal growth of the TiNx phase in an amorphous matrix, which not only simplifies the traditional multilayer process, but also achieves unexpected strengthening effects at the level of microstructure control, demonstrating significant innovation and practical value.

[0045] This invention relates to a highly wear-resistant Fe-based amorphous composite coating reinforced with a TiNx framework structure and its preparation method. The method involves designing a dual-scale powder system with structural differences, combining uniformly shaped, highly fluid Fe-based amorphous spherical powder with irregularly shaped, highly reactive Ti powder in a specific ratio, and using surface-active additives to regulate interfacial wettability, achieving uniform coating of the amorphous precursor powder by the Ti powder. In the subsequent reactive plasma spraying process, by precisely controlling the spraying process of the composite powder, the Ti powder undergoes an in-situ reaction with a nitrogen atmosphere during the high-temperature, high-speed flight phase to generate the TiNx phase. This TiNx phase spontaneously forms a penetrating framework network along the coating thickness direction and undergoes interfacial diffusion and metallurgical bonding with the amorphous matrix during high-temperature melting, thereby constructing a composite structure with a three-dimensional continuous support effect.

[0046] This skeletal structure significantly improves the interfacial bonding strength and crack resistance of the coating, and effectively suppresses the brittle fracture and oxidative wear problems of traditional amorphous coatings during friction and wear. Compared with traditional physical powder mixing and thermal spraying methods that require the introduction of a metal binder layer, this invention achieves the dual effect of "high adhesion without a binder layer + self-supporting skeletal structure reinforcement" through a powder self-construction mechanism, simplifying the process and ensuring structural stability. This coating possesses high hardness, low coefficient of friction, and excellent wear resistance, exhibiting good engineering adaptability and promotional value. Attached Figure Description

[0047] Figure 1 This is a flowchart of the present invention; Figure 2 This is a comparison diagram of the novel skeleton structure coating obtained in Embodiment 1 of the present invention and the traditional dispersion-bonded coating; Figure 3 The image shows a comparison between the novel skeleton structure coating obtained in Example 1 of this invention and the existing Fe-based amorphous coating; where (a) is the coefficient of friction; (b) is the wear track depth; and (c) is the wear mass loss. Figure 4The images show a fracture surface comparison between the novel skeleton structure coating obtained in Example 1 of this invention and an existing Fe-based amorphous coating; wherein, (a) is a fracture surface image of the Fe-based amorphous coating; (b) is a fracture surface image of the novel skeleton structure coating obtained in Example 1 of this invention; and (c) is... Figure 4 (b) is an enlarged view; (d) is... Figure 4 (b) Enlarged view; Figure 5 The images show scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses of existing Fe-based amorphous coatings; where (a) shows the wear surface morphology of the Fe-based amorphous coating; and (b) shows... Figure 5 (a) is an enlarged view; (c) is... Figure 5 (b) is an enlarged view of area B; (d) is... Figure 5 (b) is an enlarged view of area A; (e) is... Figure 5 (b) is an enlarged view of the wear debris; (f) is... Figure 5 (b) Energy dispersive spectral analysis diagrams for regions A and C; Figure 6 These are scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) images of the novel skeleton structure coating obtained in Example 1 of the present invention; wherein, (a) is the wear surface morphology of the novel skeleton structure coating obtained in Example 1 of the present invention; (b) is... Figure 6 (a) is an enlarged view; (c) is... Figure 6 (b) is an enlarged view of area D; (d) is... Figure 6 (c) Scanning electron microscope image and energy dispersive spectroscopy (EDS) analysis diagram of the wear debris. Detailed Implementation

[0048] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Example 1

[0049] like Figure 1 As shown, a TiNx skeleton structure reinforced high wear-resistant amorphous composite coating is provided. The composite coating is composed of an Fe-based amorphous matrix and a TiNx skeleton phase. The TiNx phase is distributed in a three-dimensional through-structure in the coating and forms a continuous metallurgical bond structure with the Fe-based amorphous matrix. The x=0.7 of the TiNx phase is shown.

[0050] A method for preparing a TiNx-reinforced, wear-resistant amorphous composite coating includes the following steps: S01, Fe-based amorphous alloy powder and Ti powder are mixed at a mass ratio of 20 wt.% for Ti powder and 80 wt.% for Fe-based amorphous alloy powder. S02, with the addition of a surface-active additive (polyvinyl alcohol) equivalent to 1% by mass of the mixed powder, the mixed powder is mechanically coated using high-energy ball milling technology, so that Ti powder is evenly distributed and firmly attached to the surface of Fe-based amorphous alloy powder, forming a core-shell composite powder. S03, the obtained core-shell composite powder is dried and sieved at low temperature to obtain a spray-grade composite powder with uniform particle size distribution and stable coating structure. S04, before spraying, the spray-grade composite powder is subjected to hydrogen reduction activation treatment and an active nitrogen adsorption layer is introduced to obtain the composite powder to be sprayed. S05, Substrate surface pretreatment: The substrate surface is roughened by sandblasting, and the substrate surface has micro-depressions; S06, the prepared composite powder to be sprayed is used as the spraying raw material, and plasma spraying equipment with a current of 600 A is used to deposit it on the substrate surface, with the power adjusted to 30 kW; the centerline temperature of the plasma flame is 11000 K, and the temperature decreases along the radius within a radial range of 3-10 mm, with a temperature difference of 4000-8000 K from the flame center to the edge, forming a dual gradient field of temperature and reaction within a spray distance of 100 mm; the working gas and the reaction gas are Ar / N2 mixtures, with the volume fraction of N2 controlled at 55%.

[0051] Preferably, in SO1, the particle size range of Fe-based amorphous alloy powder is 54-120 μm; and the particle size range of Ti powder is 10-25 μm.

[0052] Preferably, in S02, the high-energy ball milling technology is as follows: the ball milling time is controlled at 5 h and the rotation speed is 200 rpm.

[0053] Preferably, in S03, the process of drying and sieving at low temperature is as follows: after ball milling, the obtained core-shell composite powder is placed in an oven at 100 °C and dried for 2 h. After drying, the agglomerated particles are removed by sieving through a 100-mesh sieve to obtain a spray-grade composite powder with concentrated particle size distribution and good flowability.

[0054] Preferably, in S04, the spray-grade composite powder is placed in a forming gas containing 5% H2 / 95% Ar and kept at 350 °C for 60 min to remove the surface oxide film and expose the active metal surface; then it is maintained in a nitrogen atmosphere at 250 °C for 45 min to introduce an active nitrogen adsorption layer on the surface of the spray-grade composite powder.

[0055] A TiNx skeleton-structure-reinforced, highly wear-resistant amorphous composite coating was obtained using the preparation method of this embodiment.

[0056] This embodiment describes the application of a TiNx skeleton-reinforced, highly wear-resistant amorphous composite coating in industrial components, including bearings, gears, pump shafts, valve seats, mining crushing components, mold cavities, rail transit brake discs, and high-wear components in marine engineering.

[0057] An industrial component is prepared using a TiNx skeleton structure reinforced with a highly wear-resistant amorphous composite coating according to this embodiment.

[0058] like Figure 3 As shown, under a load of 10 N and a wear distance of 500 m, comparing the friction coefficient, sliding wear amount and wear morphology of the Fe-based amorphous coating and the Fe-based amorphous / TiNx composite coating prepared in this invention, the significant advantages of the self-constructed composite structure of this invention can be clearly demonstrated.

[0059] Figure 3 In (a), the Fe-based amorphous coating reached a stable friction stage after approximately 150 m of wear, while the composite coating of this invention tended to stabilize after approximately 80 m. The wear stage is mainly affected by the frictional resistance between micro-protrusions and the surface fit. With the accumulation of frictional heat, a surface oxide film gradually forms, and the friction coefficient decreases and tends to stabilize. Under the same experimental conditions, the average friction coefficient of the composite coating was 0.4224 ± 0.0187, significantly lower than the 0.4792 ± 0.0251 of the Fe-based amorphous coating, indicating a significant reduction in frictional resistance. Meanwhile, Figure 3 In (c), the wear mass loss of the Fe-based amorphous coating is significantly higher than that of the composite coating, showing that the composite structure significantly improves the wear resistance performance.

[0060] Figure 3 In (b), the width and depth of the wear marks on the composite coating are significantly smaller than those on the amorphous coating, indicating that it has a stronger resistance to crack propagation. This can be further confirmed by comparing the fracture morphology.

[0061] like Figure 4 As shown, Figure 4 In (a), the fracture surface of the amorphous coating is smooth and stepped, while Figure 4 In (b), the fracture surface of the composite coating exhibits a rough, undulating structure. Figure 4 (c) and Figure 4 In (d), the crack deflection and termination phenomenon at the phase interface can be observed after magnification, indicating that the three-dimensional skeleton structure formed by the TiNx phase inside the coating has a significant inhibitory effect on crack propagation.

[0062] To reveal the wear mechanism, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses were performed on the wear area. Figure 5 As shown, Figure 5In (a), the worn surface of the Fe-based amorphous coating exhibits a rough morphology, accompanied by obvious ploughing grooves and tearing marks. Figure 5 In (b), numerous microcracks and flaky spalling structures are observed in localized areas (region A). Energy dispersive spectroscopy (EDS) results show a significant increase in oxygen content in these darker regions, indicating that oxidative wear is dominant. Figure 5 (d) is Figure 5 (b) Enlarged view of area A, Figure 5 (c) is Figure 5 (b) Enlarged view of area B, Figure 5 (f) is Figure 5 (b) Energy dispersive spectroscopy (EDS) analysis of regions A and C, where, Figure 5 The left figure in (f) shows the energy dispersive spectroscopy (EDS) analysis of region A. Figure 5 The right figure in (f) shows the energy dispersive spectroscopy (EDS) analysis of region C. Figure 5 In (e), the analysis of wear debris shows that the debris is mainly flaky, with a particle size between 10 and 20 μm and a high oxygen content, indicating that the wear mechanism of the Fe-based amorphous coating is mainly due to the synergistic effect of oxidative wear and abrasive wear. The local instantaneous high temperature at the friction interface can exceed the initial crystallization temperature of the amorphous phase. In addition, the material has poor thermal conductivity, which easily leads to the formation of oxide-rich areas at microcracks, causing fatigue cracks to propagate along the oxide film interface, eventually resulting in spalling and grooves.

[0063] like Figure 6 As shown, Figure 6 In (a), the composite coating of the present invention exhibits a relatively smooth wear surface under low magnification SEM, with significantly reduced porosity and no significant furrowing or tearing damage observed, but mainly local plastic deformation. Figure 6 (b) is Figure 6 (a) Enlarged view, Figure 6 In (b), after magnifying region D, Figure 6 (c) shows a regularly arranged scale-like structure on the surface. This structure plays a role in reducing drag, resisting adhesion, and distributing shear stress during friction, and is a key manifestation of the excellent wear resistance of the composite coating.

[0064] This invention posits that the formation of this scaly structure originates from a synergistic deformation mechanism between the TiNx phase and the amorphous matrix. TiNx, as a high-strength hard phase, inhibits the initiation and propagation of microcracks under frictional loads, while the amorphous phase absorbs strain energy through localized plastic flow. The interaction at the interface between the two phases promotes the self-organization of the surface structure into a scaly configuration during sliding friction, achieving a dynamic reduction in the friction coefficient and an earlier arrival at the stable wear stage.

[0065] Furthermore, the wear debris of the composite coating also exhibits a fine, flaky structure, but the particle size is significantly smaller than that of the Fe-based amorphous coating wear debris, indicating that only the surface microstructure is worn away, while the overall skeletal structure remains stable. This "micro-peeling-self-stabilizing" mechanism allows the composite coating to maintain high integrity and a low wear rate even after wear.

[0066] At the mechanistic level, the superior performance of composite coatings is mainly attributed to the following three aspects: (1) Structural synergy: The filling-support system formed by the TiNx framework and the amorphous matrix effectively prevents crack propagation and achieves energy dissipation and strain homogenization; (2) Interface strengthening mechanism: The lattice distortion caused by the solid solution of TiNx intermetallic compounds strengthens the phase boundary bonding, reduces the free energy and interface energy, and improves the overall structural stability. (3) Self-constructed surface evolution: Under the combined action of frictional heat and shear stress, the coating surface can spontaneously form a scaly structure, realizing adaptive wear resistance and low friction control.

[0067] Figure 6 In (d), the energy dispersive spectroscopy results further indicate that a certain degree of oxidation also exists in the wear debris of the composite coating, but oxidative wear only dominates in the initial break-in stage. After the oxide film and scale structure are stably formed, the wear mode gradually changes to a stable stage dominated by slight sliding wear, exhibiting a lower coefficient of friction and smaller wear volume loss. Example 2

[0068] A TiNx skeleton-reinforced, wear-resistant amorphous composite coating is provided. The composite coating consists of an Fe-based amorphous matrix and a TiNx skeleton phase. The TiNx phase is distributed in a three-dimensional through-structure in the coating and forms a continuous metallurgical bond with the Fe-based amorphous matrix. The x=0.3 of the TiNx phase is provided.

[0069] A method for preparing a TiNx-reinforced, wear-resistant amorphous composite coating includes the following steps: S01, Fe-based amorphous alloy powder and Ti powder are mixed at a mass ratio of 10 wt.% for Ti powder and 90 wt.% for Fe-based amorphous alloy powder. S02, with the addition of a surfactant (polyethylene glycol) equivalent to 0.5% by mass of the mixed powder, the mixed powder is mechanically coated using high-energy ball milling technology, so that Ti powder is evenly distributed and firmly attached to the surface of Fe-based amorphous alloy powder, forming a core-shell composite powder. S03, the obtained core-shell composite powder is dried and sieved at low temperature to obtain a spray-grade composite powder with uniform particle size distribution and stable coating structure. S04, before spraying, the spray-grade composite powder is subjected to hydrogen reduction activation treatment and an active nitrogen adsorption layer is introduced to obtain the composite powder to be sprayed. S05, Substrate surface pretreatment: The substrate surface is roughened by sandblasting, and the substrate surface has micro-depressions; S06, the prepared composite powder to be sprayed is used as the spraying raw material, and plasma spraying equipment with a current of 650 A is used to deposit it on the substrate surface, with the power adjusted to 25 kW; the temperature of the plasma flame centerline is 9000 K, and the temperature decreases along the radius within a radial range of 3-10 mm, with a temperature difference of 4000-8000 K from the flame center to the edge, forming a dual gradient field of temperature and reaction within a spray distance of 80 mm; the working gas and the reaction gas are Ar / N2 mixtures, with the volume fraction of N2 controlled at 40%.

[0070] Preferably, in SO1, the particle size range of Fe-based amorphous alloy powder is 54-120 μm; and the particle size range of Ti powder is 10-25 μm.

[0071] Preferably, in S02, the high-energy ball milling technology is as follows: the ball milling time is controlled at 4 h and the rotation speed is 250 rpm.

[0072] Preferably, in S03, the process of drying and sieving at low temperature is as follows: after ball milling, the obtained core-shell composite powder is placed in an oven at 80 °C for 3 hours to dry. After drying, the agglomerated particles are removed by 100-mesh sieving to obtain a spray-grade composite powder with concentrated particle size distribution and good flowability.

[0073] Preferably, in S04, the spray-grade composite powder is placed in a forming gas containing 5% H2 / 95% Ar and kept at 300 °C for 90 min to remove the surface oxide film and expose the active metal surface; then it is maintained in a nitrogen atmosphere at 200 °C for 30 min to introduce an active nitrogen adsorption layer on the surface of the spray-grade composite powder.

[0074] A TiNx skeleton-structure-reinforced, highly wear-resistant amorphous composite coating was obtained using the preparation method of this embodiment.

[0075] This embodiment describes the application of a TiNx skeleton-reinforced, highly wear-resistant amorphous composite coating in industrial components, including bearings, gears, pump shafts, valve seats, mining crushing components, mold cavities, rail transit brake discs, and high-wear components in marine engineering.

[0076] An industrial component is prepared using a TiNx skeleton structure reinforced with a highly wear-resistant amorphous composite coating according to this embodiment. Example 3

[0077] A highly wear-resistant amorphous composite coating reinforced with a TiNx framework structure is disclosed. The composite coating consists of an Fe-based amorphous matrix and a TiNx framework phase. The TiNx phase is distributed in a three-dimensional through-structure in the coating and forms a continuous metallurgical bond with the Fe-based amorphous matrix. The x=1.1 of the TiNx phase is specified.

[0078] A method for preparing a TiNx-reinforced, wear-resistant amorphous composite coating includes the following steps: S01, Fe-based amorphous alloy powder and Ti powder are mixed at a mass ratio of 5 wt.% for Ti powder and 95 wt.% for Fe-based amorphous alloy powder. S02, with the addition of a surfactant (polyethylene glycol derivative) equivalent to 0.7% by mass of the mixed powder, the mixed powder is mechanically coated using high-energy ball milling technology, so that Ti powder is evenly distributed and firmly attached to the surface of Fe-based amorphous alloy powder, forming a core-shell composite powder; S03, the obtained core-shell composite powder is dried and sieved at low temperature to obtain a spray-grade composite powder with uniform particle size distribution and stable coating structure. S04, before spraying, the spray-grade composite powder is subjected to hydrogen reduction activation treatment and an active nitrogen adsorption layer is introduced to obtain the composite powder to be sprayed. S05, Substrate surface pretreatment: The substrate surface is roughened by sandblasting, and the substrate surface has micro-depressions; S06, the prepared composite powder to be sprayed is used as the spraying raw material, and plasma spraying equipment with a current of 600 A is used to deposit it on the substrate surface, with the power adjusted to 40 kW; the temperature of the plasma flame centerline is 13000 K, and the temperature decreases along the radius within a radial range of 3-10 mm, with a temperature difference of 4000-8000 K from the flame center to the edge, forming a dual gradient field of temperature and reaction within a spray distance of 120 mm; the working gas and the reaction gas are Ar / N2 mixtures, with the volume fraction of N2 controlled at 70%.

[0079] Preferably, in SO1, the particle size range of Fe-based amorphous alloy powder is 54-120 μm; and the particle size range of Ti powder is 10-25 μm.

[0080] Preferably, in S02, the high-energy ball milling technology is as follows: the ball milling time is controlled at 6 h and the rotation speed is 250 rpm.

[0081] Preferably, in S03, the process of drying and sieving at low temperature is as follows: after ball milling, the obtained core-shell composite powder is placed in an oven at 110 °C and dried for 3 hours. After drying, the agglomerated particles are removed by sieving through a 100-mesh sieve to obtain a spray-grade composite powder with concentrated particle size distribution and good flowability.

[0082] Preferably, in S04, the spray-grade composite powder is placed in a forming gas containing 5% H2 / 95% Ar and kept at 400 °C for 70 min to remove the surface oxide film and expose the active metal surface; then it is maintained in a nitrogen atmosphere at 300 °C for 60 min to introduce an active nitrogen adsorption layer on the surface of the spray-grade composite powder.

[0083] A TiNx skeleton-structure-reinforced, highly wear-resistant amorphous composite coating was obtained using the preparation method of this embodiment.

[0084] This embodiment describes the application of a TiNx skeleton-reinforced, highly wear-resistant amorphous composite coating in industrial components, including bearings, gears, pump shafts, valve seats, mining crushing components, mold cavities, rail transit brake discs, and high-wear components in marine engineering.

[0085] An industrial component is prepared using a TiNx skeleton structure reinforced with a highly wear-resistant amorphous composite coating according to this embodiment. Example 4

[0086] The only difference between this embodiment and Embodiment 1 is that: Fe-based amorphous alloy powder and Ti powder were mixed at a mass ratio of 30 wt.% for Ti powder and 70 wt.% for Fe-based amorphous alloy powder. During spraying, the volume fraction of N2 was controlled at 50%. The TiNx phase obtained in the coating had an x=0.5. Example 5

[0087] Fe-based amorphous alloy powder and Ti powder were mixed at a mass ratio of 15 wt.% for Ti powder and 85 wt.% for Fe-based amorphous alloy powder. During spraying, the volume fraction of N2 was controlled at 60%. The TiNx phase obtained in the coating had an x=0.9.

[0088] Comparative Example 1

[0089] The only difference between this comparative example and Example 1 is that the powder activation treatment was not performed by high-energy ball milling. As a result, the TiNx distribution in the coating is discrete and does not form a continuous skeleton. The porosity is as high as 7.2%, and the bonding strength is low.

[0090] like Figure 2 The figure shown is a comparison diagram between the novel skeleton structure coating obtained in Example 1 of the present invention and the traditional dispersion-bonded coating. The novel skeleton structure coating has better bonding between the two phases, the size and number of shrinkage pores are greatly reduced, and it is more tightly bonded to the matrix. The internal reaction of the reinforcing phase is more complete, and the content of unsaturated phase is reduced.

[0091] Comparative Example 2 The conventional NiCrAl adhesive layer spraying process (spraying the NiCrAl adhesive layer first and then the Fe-based functional layer) improves the bonding strength, but the density is still lacking, and the interface delamination problem still exists. In addition, there is dissimilar metal connection between the adhesive layer and the coating, which is not conducive to corrosion resistance.

[0092] Comparative Example 3

[0093] The only difference between this comparative example and Example 1 is that no hydrogen reduction activation treatment and no active nitrogen adsorption layer were introduced.

[0094] Comparative Example 4

[0095] The only difference between this comparative example and Example 1 is that: The prepared composite powder to be sprayed was used as the spraying material. The centerline temperature of the plasma flame was 8000K. Within a radial range of 3-10 mm, the temperature decreased along the radius, and the temperature difference from the flame center to the edge reached 3000-4000 K.

[0096] Comparative Example 5

[0097] The only difference between this comparative example and Example 1 is that: The prepared composite powder to be sprayed was used as the spraying material. The centerline temperature of the plasma flame was 14000 K. Within a radial range of 3-10 mm, the temperature decreased along the radius, and the temperature difference from the flame center to the edge reached 9000-10000 K.

[0098] The mechanical properties of the coatings obtained in the various embodiments and comparative examples of the present invention are shown in Table 1 below.

[0099] Table 1

[0100] In the foregoing description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this disclosure should not be construed as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, the inventive aspect lies in fewer than all the features of the foregoing disclosed embodiments. Therefore, the claims, following the detailed description, are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0101] Although the invention has been described with reference to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of interpreting or limiting the subject matter of the invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the invention is illustrative and not restrictive, and the scope of the invention is defined by the appended claims.

[0102] 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 TiNx skeleton-reinforced, highly wear-resistant amorphous composite coating, characterized in that, The composite coating consists of an Fe-based amorphous matrix and a TiNx framework phase. The TiNx phase is distributed in a three-dimensional through-structure in the coating and forms a continuous metallurgical bond with the Fe-based amorphous matrix. The x of the TiNx phase is 0.3-1.

1.

2. The method for preparing a TiNx skeleton-reinforced, highly wear-resistant amorphous composite coating according to claim 1, characterized in that, Includes the following steps: S01, Fe-based amorphous alloy powder and Ti powder are mixed at a mass ratio of 5 wt.%–30 wt.%; S02, with the addition of a surfactant equivalent to no more than 1% by mass of the mixed powder, the mixed powder is mechanically coated using high-energy ball milling technology, so that Ti powder is evenly distributed and firmly attached to the surface of Fe-based amorphous alloy powder, forming a core-shell composite powder. S03, the obtained core-shell composite powder is dried and sieved at low temperature to obtain a spray-grade composite powder with uniform particle size distribution and stable coating structure. S04, before spraying, the spray-grade composite powder is subjected to hydrogen reduction activation treatment and an active nitrogen adsorption layer is introduced to obtain the composite powder to be sprayed. S05, Substrate surface pretreatment: The substrate surface is roughened by sandblasting, and the substrate surface has micro-depressions; S06, the prepared composite powder to be sprayed is used as the spraying raw material, and plasma spraying equipment with a current of not less than 600 A is used to deposit it on the substrate surface. The power adjustment range is between 25-40 kW. The centerline temperature of the plasma flame is 9000-13000 K. In the radial range of 3-10 mm, the temperature decreases along the radius. The temperature difference from the flame center to the edge is 4000-8000 K. A dual gradient field of temperature and reaction is formed in the range of 80-120 mm of spray distance. The working gas and the reaction gas are Ar / N2 mixtures, and the volume fraction of N2 is controlled at 40%-70%.

3. The preparation method according to claim 2, characterized in that, In S01, the particle size range of Fe-based amorphous alloy powder is 54-120 μm; the particle size range of Ti powder is 10-25 μm.

4. The preparation method according to claim 2, characterized in that, In SO2, the surfactants include polyvinyl alcohol organic surfactants; polyvinyl alcohol organic surfactants include polyvinyl alcohol, polyethylene glycol or their derivatives; the amount of surfactants added is 0.5-1%.

5. The preparation method according to claim 2, characterized in that, In S02, the high-energy ball milling technology is as follows: the ball milling time is controlled at 4-6 hours and the rotation speed is 200-250 rpm.

6. The preparation method according to claim 2, characterized in that, In S03, the process of drying and sieving at low temperature is as follows: After ball milling, the obtained core-shell composite powder is placed in an oven at 80-110 °C and dried for 2-3 hours. After drying, the agglomerated particles are removed by 100-mesh sieving to obtain a spray-grade composite powder with concentrated particle size distribution and good flowability.

7. The preparation method according to claim 2, characterized in that, In S04, the spray-grade composite powder is placed in a forming gas containing 5% H2 / 95% Ar and kept at 300-400 °C for at least 60 min to remove the surface oxide film and expose the active metal surface; then it is maintained in a nitrogen atmosphere at 200-300 °C for 30-60 min to introduce an active nitrogen adsorption layer on the surface of the spray-grade composite powder.

8. A TiNx skeleton-reinforced, highly wear-resistant amorphous composite coating obtained by the preparation method according to any one of claims 2 to 7, characterized in that, The coating has a coefficient of friction of 0.39-0.42, a porosity of 3.9-4.2%, and a hardness of 1080-1115 HV. 0.2 The bonding strength is 28.48-29.32 MPa.

9. The application of the TiNx skeleton-reinforced, highly wear-resistant amorphous composite coating according to claim 8 in industrial components, characterized in that, Industrial components include bearings, gears, pump shafts, valve seats, mining crushing components, mold cavities, rail transit brake discs, and high-wear components in marine engineering.

10. An industrial component, prepared using a TiNx skeleton structure reinforced with a highly wear-resistant amorphous composite coating as described in claim 8.

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