A bionic corrugated layered Fe-based amorphous composite coating and a preparation method and application thereof

Abstract

This invention discloses a biomimetic corrugated layered Fe-based amorphous composite coating, its preparation method, and its application, belonging to the fields of materials science and surface engineering technology. The biomimetic corrugated layered Fe-based amorphous composite coating has a periodically staggered corrugated layered structure along its thickness direction, consisting of alternating TiNx-rich layers and amorphous-rich layers; each layer has a transition layer with a thickness of 20-40 μm between it and the others; the total coating thickness is 300-400 μm; the thickness of the TiNx-rich layer is 50-80 μm; in the TiNx-rich layer, the TiNx reinforcing phase is uniformly distributed with a particle size between 50-200 nm; the thickness of the amorphous-rich layer is 80-120 μm. This invention achieves natural stratification and interfacial synergy between the amorphous phase and the TiNx phase in the thickness direction by controlling the powder particle size distribution, spraying distance, plasma hydrodynamic parameters, and additive atmosphere, forming a composite coating with a significant crack-blocking effect.

Description

Technical Field

[0001] This invention belongs to the field of materials science and surface engineering technology, specifically relating to a structurally reinforced Fe-based amorphous composite coating and its preparation method. The coating achieves a "shell-like" multi-scale structure through controllable layered / transition phase design and in-situ chemical reaction, thereby simultaneously obtaining high hardness, high strength, and significantly improved fracture toughness. It is suitable for marine engineering, nuclear power equipment, pumps and valves, ships, and other harsh service environments requiring wear resistance, corrosion resistance, and impact resistance. Background Technology

[0002] Fe-based amorphous alloys, with their boundary-free, uniform atomic structure, exhibit excellent corrosion resistance and high hardness, thus attracting widespread attention in the field of protective coatings. Plasma spraying, as an effective method for rapidly constructing thick amorphous coatings on substrate surfaces, can significantly improve the wear and corrosion resistance of component surfaces in a short time. However, existing Fe-based amorphous coatings still face the following key bottlenecks in practical engineering applications:

[0003] (1) Amorphous phases lack grain boundaries and dislocation slip mechanisms, making it difficult to effectively dissipate strain energy, which makes the coating prone to sudden brittle fracture under stress, seriously affecting service reliability;

[0004] (2) To improve overall performance, multi-layer or composite structure design is often adopted, but simple stacking often leads to weak metallurgical bonding at the interface and serious thermal expansion mismatch, thus forming a new failure initiation point;

[0005] (3) Traditional premixed powder spraying methods are prone to agglomeration of reinforcing phase, uneven distribution or incomplete reaction, making it difficult to form an ideal gradient or periodic layered structure;

[0006] (4) The layered structure is achieved by repeatedly changing the powder source or by complex steps, which results in complicated processes, poor repeatability, and limited industrialization capabilities.

[0007] To overcome the aforementioned problems, there is an urgent need for a preparation method that can control phase boundary and defect density at the microscale and achieve periodic layered or gradient reinforcement at the macroscale, enabling Fe-based amorphous coatings to achieve higher fracture toughness and service stability while maintaining their original corrosion and wear resistance properties. In particular, forming an ordered interlayer connection between high-performance nitride-reinforced phases and amorphous phases through in-situ reactions, i.e., a "shell-like" structure, is considered a feasible path with toughening potential. However, existing publicly available technologies have not yet provided a complete solution for stable and controllable spraying sources, interlayer transition phase regulation, and nitride reaction control.

[0008] Recent studies have shown that corrugated layered structures can guide stress deflection and dispersion along the interface during loading, forming complex energy dissipation paths, thereby significantly inhibiting linear crack propagation and interface debonding. This structure simulates the natural layering pattern of "hard-tough alternation" in shells, enabling coatings to possess excellent crack resistance and impact toughness while maintaining high hardness and strength. Therefore, introducing corrugated layered structures into the design of Fe-based amorphous composite coatings not only helps achieve multi-scale toughening and adaptive stress regulation, but also provides a new structural approach to overcome the brittleness limitations of traditional amorphous coatings. Summary of the Invention

[0009] In this invention, a plasma spraying method based on gravity dispersion and in-situ reaction coupling (i.e., a method for preparing a biomimetic corrugated layered Fe-based amorphous composite coating) is employed, using Fe-based amorphous alloy powder (preferably Fe...) 48 Cr 23 Mo 10 C 14 Using B5 (at.%) and TiH2 powder as composite raw materials, and introducing nitriding promoters, the simultaneous in-situ formation of TiNx (0.3 ≤ x ≤ 1.1) reinforcing phase and corrugated layered structure was achieved during a single-step deposition process. This process, by controlling powder particle size distribution, spraying distance, plasma hydrodynamic parameters, and promoter atmosphere, achieved natural stratification and interfacial synergy between the amorphous phase and the TiNx phase in the thickness direction, forming a composite coating with a significant crack-blocking effect.

[0010] In terms of the material system, Fe-based amorphous powder with a particle size of 20-54 μm and TiH2 powder with a particle size of 10-30 μm (Fe48Cr23Mo10C14B5 (at.%) amorphous alloy powder provided by Guangzhou Wandun Amorphous Trading Co., Ltd., and TiH2 powder provided by Beijing Zhongnuo New Materials Co., Ltd.) were selected. The mass ratio of TiH2 was 17.6-21.7%, with the balance being Fe-based amorphous powder. The mixture was centrifuged. To promote the rapid decomposition of TiH2 in the plasma flow and enhance the nitriding reaction efficiency, 0.5-1.0 wt.% (equivalent to 0.5-1.0 wt.% of the total weight of Fe-based amorphous powder and TiH2 powder) of active nitriding aid was added during the mixing process. This additive is prepared by premixing boron nitride (BN) and an amino organic salt (such as NH4C2H3O2, ammonium acetate) at a mass ratio of 3:1, and then pyrolyzing them in an inert atmosphere at 580-720°C (preferably 700°C) for 100-140 min (preferably 2 h) to obtain a porous active nitriding additive. This additive releases NH2 free radicals in the high-temperature zone of the spraying process, which can establish a nitrogen-rich reaction gas field on the outer layer of the particles in a short time, significantly increasing the reaction probability between Ti and nitrogen atoms after TiH2 dehydrogenation. This results in the formation of a metastable TiNx phase with some sub-nitrogen vacancies and nitrogen vacancy clusters, rather than the traditional cubic TiN structure. Experiments show that when x is controlled in the range of 0.3-1.1, the distortion of Ti–N–Ti bridge bonds and local nitrogen vacancies formed in the resulting TiNx lattice contribute to the passivation and propagation of cracks at the interface, the so-called "crack blocking effect," which can significantly improve interfacial energy consumption and fracture toughness.

[0011] The spraying process utilizes a high-energy plasma system (current 640-660 A, voltage 47-53 V), with a working gas system of Ar + He + N2 ternary mixture. Ar is the primary gas (42-56 psi), He is the auxiliary gas (65-75 psi), and N2 serves as both the reaction source and carrier gas (55-65 psi), coupled with a powder feed rate of 18-22 g / min. Under this combination, the plasma arc core temperature can reach 1.2 × 10⁻⁶. 4 -1.4×10 4 K ensures complete dehydrogenation of TiH2 powder during flight, while providing a rapid heating and cooling environment for Fe-based amorphous powder, preventing crystallization tendency. A horizontal spraying method is employed, with the spray gun's main axis perpendicular to the direction of gravity, and the spraying distance maintained at 80-130 mm (preferably 100 ± 10 mm) to ensure that the powder retains some liquefaction characteristics before reaching the substrate, achieving simultaneous droplet impact spreading and rapid solidification.

[0012] To achieve spontaneous gravity-induced stratification of the powder during deposition, this invention employs a horizontal spraying method, where the spray gun's main axis is perpendicular to the direction of gravity. Although there is no angle between the particle motion direction and the direction of gravity, in a high-speed plasma flow field, the gas velocity distribution exhibits a significant radial gradient, with the highest gas velocity in the core region and stronger turbulence and lower velocity in the peripheral region. The high-density Fe-based amorphous powder (7.3 g·cm³) is used. -3 In this flow field, after being slightly perturbed by gravity, its trajectory shifts slightly downward relative to the main axis; while the less dense TiH2 and additive powder (3.8-4.0 g·cm³) -3 The two particles are more likely to move forward with the central region of the main airflow. Under the shearing action of the flow field, they form a slightly layered flow band perpendicular to the spray direction, resulting in a particle flow field with alternating distribution of amorphous and TiH2-rich particles in the spray terminal region.

[0013] When the mixed powder enters the high-temperature plasma zone, TiH2 particles rapidly dehydrogenate to generate active Ti, while the active nitriding agent simultaneously releases NH2 free radicals. In the locally high-temperature, nitrogen-rich environment, this promotes an in-situ reaction between Ti and N to generate a non-stoichiometric TiNx (0.3 ≤ x ≤ 1.1) nanophase. Due to the local enrichment of amorphous powder in the lower region of the jet, it arrives at the substrate surface first and forms the bottom layer deposition. Subsequently, TiH2 and additive powder located in the upper part of the gas flow react and deposit on top, forming a TiNx-rich layer. As the spraying continues, newly arriving amorphous droplets cover the previous TiNx layer, while the reacted TiNx particles are deposited and covered in the upper gas flow, ultimately forming a periodically alternating TiNx-rich layer and an amorphous-rich layer in the thickness direction.

[0014] Stable control of spraying power and heat input plays a crucial role in the formation of the corrugated layered structure. In this invention, the plasma arc spraying current is maintained within the range of 640-660 A, and the gas flow rate and powder delivery rate are precisely matched to ensure that the particle swarm obtains stable and repeatable heat input conditions in the high-temperature region. Fe-based amorphous powder rapidly melts under the shearing action of the airflow to form highly fluid droplets, while TiH2 powder and active nitriding additives gradually react in the high-temperature plasma flow to generate TiNx nanophases. Due to differences in powder particle size, density, and gas resistance, the particles form a light-heavy separation distribution in the airflow: the denser amorphous powder tends to move closer to the center of the flow field, while the less dense TiH2 and additive powders are more easily dispersed in the edge region of the flow field, thus forming local compositional stratification at the deposition front.

[0015] To maintain the uniformity of macroscopic deposition, the spray gun performs reciprocating planar scanning along the substrate surface, with the trajectory overlap rate controlled at 40%-50% and the scanning speed at 80-150 mm / s. -1 (Preferred 100 mm·s) -1Due to the influence of local gas backflow and shear vortices, the top of the deposited TiNx layer is partially eroded or covered by subsequent amorphous droplets, forming localized interlacing regions. This process causes the interlayer interface to exhibit periodic wavy undulations, rather than being completely flat, effectively avoiding sharp interface transitions. The final composite coating exhibits a wavy layered structure at the microscale, while maintaining a continuous, dense, and uniform morphology at the macroscale.

[0016] The timescale of in-situ reactions in high-temperature plasma streams is extremely short (approximately 10). -3 The reaction is on the order of s (in terms of magnitude), but its reaction kinetics can be controlled by the rate constants of the TiH2 dehydrogenation and Ti–N reactions. Calculations show that at 12000 K, the rate constant k1 ≈ 3.2 × 10⁻⁶. 5 s -1 The reaction rate constant k2 between Ti and N2 is approximately 4.8 × 10⁻⁶. 4 s -1 Therefore, a TiNx shell structure with a thickness of about tens of nanometers can be formed within a flight time of about 1.5 ms. During deposition, this structure undergoes a short-range diffusion reaction with the amorphous droplet interface to form a transition layer with a thickness of about 20-40 μm, containing a Cr–Ti–N ternary solid solution phase, which has both good chemical bonding and elastic matching, thus significantly improving the interfacial bonding toughness.

[0017] The final coating exhibits a corrugated layered structure at the microscopic level, with a total layer thickness of approximately 300-400 μm and a TiNx-rich layer thickness of 50-80 μm. At the interface, the TiNx-reinforcing phase is uniformly distributed with a particle size between 50-200 nm, and the amorphous-rich layer thickness is 80-120 μm. Figure 1 , 2 As shown, due to the nitrogen vacancies and ion defects present in TiNx, its elastic modulus (approximately 300-380 GPa) is slightly lower than that of traditional TiN (approximately 450 GPa), enabling it to undergo microscopic plastic deformation under external loads, thereby achieving stress dissipation and blockage at the crack tip. The amorphous layer supports the TiNx layer with its high elastic recovery capability and fracture toughness, forming a microstructure characterized by alternating "hard phase-tough phase" distribution. This structure significantly improves the coating's impact resistance, fracture toughness, and elastic modulus matching, while also exhibiting excellent passivation stability in corrosive media.

[0018] In summary, this method, by introducing nitriding promoters and gravity-induced layered deposition into the spraying system, achieves efficient in-situ generation of TiNx (0.3 ≤ x ≤ 1.1) strengthening phases and self-organized evolution of corrugated layered structures. Unlike traditional plasma spraying or dual-channel reactive spraying, this process requires no additional spraying channels or complex control systems. Relying solely on the reasonable matching of powder system design and spraying distance, it can simultaneously achieve layered structure construction and performance optimization in a single-step deposition process, providing a new and feasible technical route for the preparation of high-toughness Fe-based amorphous composite coatings.

[0019] The present invention has the following beneficial effects:

[0020] This invention provides a Fe-based amorphous composite coating prepared using a reactive plasma spraying process. By introducing a density-differential-induced gravity-induced stratification effect and an in-situ reaction mechanism enhanced by an active nitriding agent, a self-organized deposition process of TiH2 and Fe-based amorphous powder is achieved under horizontal spraying conditions. The resulting coating exhibits a stable corrugated layered gradient structure and excellent overall performance. Compared with traditional Fe-based amorphous coatings, this invention demonstrates significant innovation in structural construction, reaction control mechanism, and performance balance.

[0021] In terms of structural design, the coating prepared by this invention exhibits a periodically staggered corrugated layered structure along its thickness direction, consisting of alternating TiNx-rich and amorphous-rich layers. Transition zones are formed between the layers through in-situ reactions at high temperatures, achieving a robust metallurgical bond. The TiNx reinforcing phase is distributed in a locally continuous state, mainly concentrated at the interlayer interfaces and transition zones, creating a flexible transition structure and energy buffer at the interfaces. When external forces are applied, the corrugated interfaces induce stress deflection and dispersion, forcing crack propagation paths to undergo multiple turns and bifurcations, thereby effectively suppressing brittle fracture and improving overall fracture toughness. This structure achieves a synergistic effect of "hard phase bearing capacity - tough phase energy absorption" in localized regions, significantly improving the coating's impact and peel resistance.

[0022] In terms of process method, this invention adopts a single-step reactive deposition method, eliminating the need for complex multi-layer spraying or subsequent heat treatment. By adjusting the spraying parameters and powder ratio, Fe-based amorphous powder, TiH2, and active nitriding aids undergo simultaneous heating, reaction, and deposition processes within the high-temperature region of a plasma arc, forming a corrugated layered structure with periodic undulations. The active nitriding aid releases NH2 free radicals in the high-temperature environment, significantly promoting the dehydrogenation and nitriding reactions of TiH2, thereby generating a metastable TiNx phase (0.3 ≤ x ≤ 1.1) containing partially nitrogen-vacancy clusters. These metastable phase particles are dispersed on the surface of the amorphous substrate and in the interlayer region, constructing periodically alternating TiNx-rich and amorphous-rich layers. Lattice defects in the TiNx phase can absorb strain energy at the crack tip and inhibit crack propagation, endowing the coating with excellent fracture toughness and structural stability. This method achieves simultaneous synergy of powder layering, in-situ reaction, and deposition, simplifying the process and ensuring good repeatability.

[0023] In terms of performance, the composite coating combines the excellent corrosion resistance of the Fe-based amorphous phase with the high hardness, toughness, and thermal stability of the TiNx metastable phase. The TiNx reinforced layer effectively improves the elastic modulus and wear resistance of the surface layer, while the corrugated interface structure significantly improves stress distribution, avoiding interface failure caused by thermal stress concentration in traditional coatings. The elastic modulus of the interface region exhibits a gradient transition characteristic, maintaining both the ductility of the amorphous layer and the high stiffness of the TiNx layer, thus achieving a synergy of high hardness and high toughness on a macroscopic level.

[0024] In summary, this invention achieves dual optimization of Fe-based amorphous composite coatings in terms of structural hierarchy and performance matching through an integrated strategy of "density stratification + nitrogen-assisted reaction + corrugated layer construction". The resulting coating has high strength, high toughness and excellent interfacial stability, good engineering adaptability and mass production potential, and can be widely used in the field of surface strengthening and protection under high load, strong corrosion and high abrasion environments.

[0025] This invention discloses a corrugated layered Fe-based amorphous composite coating and its preparation method based on a synergistic mechanism of gravity stratification and in-situ reaction. The method employs reactive plasma spraying technology, using Fe-based amorphous alloy powder and TiH2 powder as main raw materials, and introducing an active nitriding agent. By rationally matching the powder density, particle size distribution, and spraying distance, the powder is subjected to gravitational perturbation during horizontal spraying, forming a vertically stratified flow field that promotes the alternating deposition of the Fe-based amorphous phase and the reaction products of TiH2 along the thickness direction. In the high-temperature plasma flow, TiH2 rapidly dehydrogenates to generate active Ti, and the active nitriding agent releases NH2 free radicals to promote the in-situ nitriding reaction, generating a metastable strengthening phase of TiNx (0.3≤x≤1.1) containing partially nitrogen-vacancy clusters. This process achieves simultaneous powder stratification, reaction generation, and deposition, thereby spontaneously constructing a periodic corrugated layered composite structure. A stable metallurgical transition zone is formed between the TiNx strengthening layer and the Fe-based amorphous layer, significantly improving the coating's bonding strength, fracture toughness, and impact resistance. The coating obtained by this invention has a dense and uniform layered structure and excellent corrosion resistance, wear resistance and crack resistance, and is suitable for surface strengthening and protection in high load, strong corrosion and high abrasion environments. Attached Figure Description

[0026] Figure 1 This is a cross-sectional topography (150 μm) of the coating obtained in Example 1 of the present invention.

[0027] Figure 2 This is a cross-sectional topography (20 μm) of the coating obtained in Example 1 of the present invention.

[0028] Figure 3 The diagram shows a three-point bending experiment, where (a) is the amorphous coating; and (b) is the coating obtained in Example 1 of the present invention.

[0029] Figure 4 The images show the tensile fracture morphology of the coatings, where (a) is an amorphous coating and (b) is the coating obtained in Example 1 of the present invention.

[0030] Figure 5 for Figure 4 (b) is a magnified view of a portion of the image;

[0031] Figure 6 This is an electrochemical test diagram. Detailed Implementation

[0032] 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

[0033] A biomimetic corrugated layered Fe-based amorphous composite coating, wherein the coating has a periodically staggered corrugated layered structure along the thickness direction, consisting of alternating TiNx-rich layers and amorphous-rich layers.

[0034] There is a transition layer with a thickness of about 20 μm between each layer, and the transition layer contains a Cr–Ti–N ternary solid solution phase;

[0035] The total coating thickness is approximately 300 μm;

[0036] The thickness of the TiNx-rich layer is about 50 μm; in the TiNx-rich layer, the TiNx reinforcing phase is uniformly distributed and the particle size is between 50-200 nm;

[0037] The thickness of the amorphous layer is around 80 μm.

[0038] Preferably, in TiNx, x = 0.3.

[0039] The coating in this embodiment has an elastic modulus of 300 GPa and a bonding strength between the coating and the substrate of 40.3 MPa.

[0040] A method for preparing a biomimetic corrugated layered Fe-based amorphous composite coating includes the following steps: Step 1, selecting Fe-based amorphous powder (Fe...) with a particle size of 20-54 μm. 48 Cr 23 Mo 10 C 14 B5) and 10-30 μm TiH2 powder, with TiH2 accounting for 20% by mass, Fe-based amorphous powder (Fe 48 Cr 23 Mo 10 C 14 B5) is mixed at a mass ratio of 80%. During the mixing process, an active nitriding agent equivalent to 0.5 wt.% of the total weight of Fe-based amorphous powder and TiH2 powder is added. After uniform mixing, a spray powder is obtained. Step 2: Spraying, current 650 A, voltage 50 V, working gas is a ternary mixture of Ar + He + N2, where Ar is the main gas with a flow rate of 50 psi, He is the auxiliary gas with a flow rate of 70 psi, and N2 is used as the reaction source gas and carrier gas with a flow rate of 60 psi. With a powder feeding rate of 20.8 g / min, the plasma arc core temperature reaches 1.23 × 10⁻⁶. 4 K employs a horizontal spraying method, ensuring the spray gun's spindle is perpendicular to the direction of gravity, maintaining a spraying distance of 110mm, and performing a reciprocating planar scan along the substrate surface with a trajectory overlap rate controlled at 45% and a scanning speed of 100mm / s. -1 .

[0041] Preferably, the active nitriding agent is prepared by premixing boron nitride (BN) and ammonium acetate (NH4C2H3O2) at a mass ratio of 3:1, and then pyrolyzing them at 700°C for 120 min in an inert atmosphere to obtain a porous active nitriding agent.

[0042] This embodiment describes the application of a biomimetic corrugated layered Fe-based amorphous composite coating in harsh service environments. These harsh service environments include marine engineering, nuclear power equipment, pumps and valves, and ships.

[0043] Implementation effect verification:

[0044] like Figure 1 , 2 As shown, experimental results indicate that the Fe-based amorphous composite coating prepared in this embodiment is dense and uniform in structure, with a smooth and continuous interface. No obvious pores or delamination defects were observed on the coating cross-section, demonstrating excellent film quality and interface stability. Bond strength tests showed that the bonding strength between the coating and the substrate reached 40.3 MPa, significantly higher than both the traditional Fe-based amorphous coating (approximately 32 MPa) and the dispersion-structured composite coating (approximately 25 MPa). This enhancement is mainly attributed to the continuous metallurgical transition zone formed between the TiNx phase generated in situ and the Fe-based amorphous matrix. Some Cr elements (derived from alloying elements in the Fe-based amorphous powder) participate in Ti-N bond bonding in the interface region, further improving interface matching and bonding strength.

[0045] The three-point bending test results further verified the mechanical robustness of the layered structure. During loading, the coating exhibited progressive failure behavior, without sudden brittle fracture (e.g., ...). Figure 3 (As shown). Fracture morphology observation revealed that the Fe-based amorphous layer exhibited a relatively smooth fracture surface, while the TiNx reinforced layer region showed fine tearing and wavy undulations, indicating that the crack deflected and bifurcated when crossing the TiNx / amorphous interface. Local magnification observation showed that the crack tip was significantly blunted within the metastable TiNx phase, accompanied by obvious micro-plastic deformation and energy dissipation, effectively hindering rapid crack propagation (e.g., Figure 4 , 5 (As shown). Therefore, the layered gradient structure can form a multi-path energy dissipation and stress buffering mechanism under external load, which significantly improves the fracture toughness and impact resistance of the coating. The fracture displacement of the coating is about 0.17 mm, which is about 88.9% higher than that of a single-layer amorphous coating, further confirming its excellent crack resistance.

[0046] Electrochemical testing results showed that the corrugated layered Fe-based amorphous composite coating exhibited superior corrosion resistance compared to the dispersed composite coating in 3.5 wt.% NaCl solution. Polarization curves revealed a significant positive shift in its self-corrosion potential, with a corrosion current density of only 3.67 × 10⁻⁶.-6 A / cm 2 Compared to the dispersed structure coating (7.13×10), -6 A / cm 2 The value was reduced by about half, and compared with a single-layer Fe-based amorphous coating (3.83 × 10⁻⁶). -6 A / cm 2 Basically unchanged (e.g.) Figure 6 (As shown). Long-term immersion experiments further revealed the advantages of this structure in terms of corrosion resistance: after 1000 h of immersion, the surface of the corrugated layered composite coating remained intact, with no obvious pitting or peeling, and the corrosion current density remained at 6.97 × 10⁻ -6 A / cm 2 Slight rust spots (8.52×10) have appeared on the surface of the amorphous coating. -6 A / cm 2 In the dispersed structure sample, localized film damage occurred, with a corrosion current as high as 18.42 × 10⁻⁶. -6 A / cm 2 This excellent corrosion resistance is mainly attributed to the chemical stability of the dense oxynitride film formed on the surface of the TiNx reinforced layer, and the effective suppression of ion penetration and interfacial electric field stress by the periodic interlaced structure, thereby significantly improving the corrosion durability and service life of the coating.

[0047] The above-mentioned dispersion structure coating is prepared by mechanically mixing Fe-based amorphous alloy powder (Fe... 48 Cr 23 Mo 10 C 14 B5) and Ti powder are mixed evenly at a mass ratio of 4:1 and used as a spraying material.

[0048] During the spraying process, the spray gun spindle is parallel to the direction of gravity (i.e., perpendicular to the substrate surface) to deposit the coating, forming a diffused composite coating.

[0049] Spraying parameters: current 650 A, voltage 50 V, working gas is a ternary mixture of Ar + He + N2, where Ar is the main gas (flow rate 45 psi), He is the auxiliary gas (flow rate 68 psi), and N2 is used as the reaction source and carrier gas (flow rate 70 psi); powder feed rate is 20.8 g / min, spraying distance is maintained at 110 mm, trajectory overlap is controlled at 45%, and scanning speed is 100 mm·s. -1 .

[0050] The above-mentioned traditional method for preparing Fe-based amorphous coatings is as follows: Fe-based amorphous alloy powder (Fe... 48 Cr 23 Mo 10 C 14 B5) is used as a coating material.

[0051] During the spraying process, the spray gun spindle is parallel to the direction of gravity (i.e., perpendicular to the substrate surface) for deposition.

[0052] The spraying parameters were: current 650 A, voltage 50 V, and working gas was a ternary mixture of Ar + He + N2, where Ar was the main gas (flow rate 45 psi), He was the auxiliary gas (flow rate 68 psi), and N2 served as both the reaction source and carrier gas (flow rate 70 psi). The powder feed rate was 20.8 g / min, the spraying distance was maintained at 110 mm, the trajectory overlap was controlled at 45%, and the scanning speed was 100 mm / s. -1 .

[0053] In summary, the experimental results fully demonstrate the effectiveness of the structural design and process route proposed in this invention. The prepared Fe-based amorphous composite coating achieves stable distribution of the reinforcing phase and coordination of interfacial stress while maintaining the high strength of the amorphous matrix, exhibiting excellent crack resistance, impact resistance, and corrosion resistance. This design concept provides a new technical path for the layered construction and engineering application of amorphous matrix composite coatings. Example 2

[0054] A biomimetic corrugated layered Fe-based amorphous composite coating, wherein the coating has a periodically staggered corrugated layered structure along the thickness direction, consisting of alternating TiNx-rich layers and amorphous-rich layers.

[0055] There is a transition layer with a thickness of about 30 μm between each layer, and the transition layer contains a Cr–Ti–N ternary solid solution phase;

[0056] The total coating thickness is approximately 350 μm;

[0057] The thickness of the TiNx-rich layer is about 65 μm; in the TiNx-rich layer, the TiNx reinforcing phase is uniformly distributed and the particle size is between 50-200 nm;

[0058] The thickness of the amorphous layer is around 100 μm.

[0059] Preferably, in TiNx, x = 0.7.

[0060] The coating in this embodiment has an elastic modulus of 350 GPa and a bonding strength between the coating and the substrate of 42.6 MPa.

[0061] A method for preparing a biomimetic corrugated layered Fe-based amorphous composite coating includes the following steps: Step 1, selecting Fe-based amorphous powder (Fe...) with a particle size of 20-54 μm. 48 Cr 23 Mo 10 C 14B5) and 10-30 μm TiH2 powder, with TiH2 accounting for 17.6% by mass, Fe-based amorphous powder (Fe 48 Cr 23 Mo 10 C 14 B5) accounts for 82.4% of the total mass and is mixed. During the mixing process, an active nitriding agent equivalent to 0.8 wt.% of the total weight of Fe-based amorphous powder and TiH2 powder is added. After uniform mixing, a spray powder is obtained. Step 2: Spraying, current 640A, voltage 47V, working gas is a ternary mixture of Ar + He + N2, where Ar is the main gas with a flow rate of 42 psi, He is the auxiliary gas with a flow rate of 65 psi, and N2 is used as the reaction source gas and carrier gas with a flow rate of 55 psi. With a powder feeding rate of 18 g / min, the plasma arc core temperature reaches 1.2 × 10⁻⁶. 4 K employs a horizontal spraying method, ensuring the spray gun's spindle is perpendicular to the direction of gravity, maintaining a spraying distance of 80mm, and performing a reciprocating planar scan along the substrate surface with a trajectory overlap rate controlled at 40% and a scanning speed of 80mm / s. -1 .

[0062] Preferably, the active nitriding agent is prepared by premixing boron nitride (BN) and ammonium acetate (NH4C2H3O2) at a mass ratio of 3:1, and then pyrolyzing them at 580°C for 100 min in an inert atmosphere to obtain a porous active nitriding agent.

[0063] This embodiment describes the application of a biomimetic corrugated layered Fe-based amorphous composite coating in harsh service environments. These harsh service environments include marine engineering, nuclear power equipment, pumps and valves, and ships. Example 3

[0064] A biomimetic corrugated layered Fe-based amorphous composite coating, wherein the coating has a periodically staggered corrugated layered structure along the thickness direction, consisting of alternating TiNx-rich layers and amorphous-rich layers.

[0065] There is a transition layer with a thickness of about 40 μm between each layer, and the transition layer contains a Cr–Ti–N ternary solid solution phase;

[0066] The total coating thickness is approximately 400 μm;

[0067] The thickness of the TiNx-rich layer is about 80 μm; in the TiNx-rich layer, the TiNx reinforcing phase is uniformly distributed and the particle size is between 50-200 nm;

[0068] The thickness of the amorphous layer is around 120 μm.

[0069] Preferably, in TiNx, x = 1.1.

[0070] The coating in this embodiment has an elastic modulus of 380 GPa and a bonding strength between the coating and the substrate of 41.9 MPa.

[0071] A method for preparing a biomimetic corrugated layered Fe-based amorphous composite coating includes the following steps: Step 1, selecting Fe-based amorphous powder (Fe...) with a particle size of 20-54 μm. 48 Cr 23 Mo 10 C 14 B5) and 10-30 μm TiH2 powder, with TiH2 accounting for 21.7% by mass, Fe-based amorphous powder (Fe 48 Cr 23 Mo 10 C 14 B5) accounts for 78.3% of the total mass and is mixed. During the mixing process, an active nitriding agent equivalent to 1.0 wt.% of the total weight of Fe-based amorphous powder and TiH2 powder is added. After uniform mixing, a sprayable powder is obtained. Step 2: Spraying, current 660 A, voltage 53 V, working gas is a ternary mixture of Ar + He + N2, where Ar is the main gas with a flow rate of 56 psi, He is the auxiliary gas with a flow rate of 75 psi, and N2 is used as the reaction source gas and carrier gas with a flow rate of 65 psi. With a powder feeding rate of 22 g / min, the plasma arc core temperature reaches 1.4 × 10⁻⁶. 4 K employs a horizontal spraying method, ensuring the spray gun's spindle is perpendicular to the direction of gravity, maintaining a spraying distance of 130mm, and performing a reciprocating planar scan along the substrate surface with a trajectory overlap rate controlled at 50% and a scanning speed of 150mm / s. -1 .

[0072] Preferably, the active nitriding agent is prepared by premixing boron nitride (BN) and ammonium acetate (NH4C2H3O2) at a mass ratio of 3:1, and then pyrolyzing them at 720°C for 140 min in an inert atmosphere to obtain a porous active nitriding agent.

[0073] This embodiment describes the application of a biomimetic corrugated layered Fe-based amorphous composite coating in harsh service environments. These harsh service environments include marine engineering, nuclear power equipment, pumps and valves, and ships. Example 4

[0074] The only difference between this embodiment and Embodiment 1 is that the spraying distance is maintained at 100mm. Example 5

[0075] The only difference between this embodiment and Embodiment 1 is that the spraying distance is maintained at 90mm.

[0076] 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 features of the foregoingly 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.

[0077] 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.

[0078] 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 method for preparing a biomimetic corrugated layered Fe-based amorphous composite coating, characterized in that, The coating has a corrugated layered structure with periodic staggered distribution along the thickness direction, consisting of alternating TiNx-rich layers and amorphous-rich layers; There is a transition layer with a thickness of 20-40 μm between each layer, and the transition layer contains a Cr–Ti–N ternary solid solution phase; The total coating thickness is 300-400μm; The thickness of the TiNx-rich layer is 50-80 μm; in the TiNx-rich layer, the TiNx reinforcing phase is uniformly distributed and the particle size is between 50-200 nm; The thickness of the amorphous layer is 80-120 μm; In TiNx, 0.3 ≤ x ≤ 1.1; The preparation method includes the following steps: Step 1: Select Fe-based amorphous powder with a particle size of 20-54 μm and TiH2 powder with a particle size of 10-30 μm, with the mass ratio of TiH2 being 17.6-21.7%, and mix them. During the mixing process, add an active nitriding agent equivalent to 0.5-1.0 wt.% of the total weight of the Fe-based amorphous powder and TiH2 powder, and mix evenly to obtain the spraying powder. Step two, spraying, with a current of 640-660 A, a voltage of 47-53 V, and a working gas system of Ar + He + N2 ternary mixture, where Ar is the main gas with a flow rate of 42-56 psi, He is the auxiliary gas with a flow rate of 65-75 psi, and N2 is used as the reaction source gas and carrier gas with a flow rate of 55-65 psi; the powder feeding rate is 18-22 g / min, and the plasma arc core temperature reaches 1.2 × 10⁻⁶. 4 -1.4×10 4 K. A horizontal spraying method is adopted, with the spray gun spindle perpendicular to the direction of gravity, the spraying distance maintained at 80-130mm, and the spray gun performing a reciprocating planar scan along the substrate surface, with the trajectory overlap rate controlled at 40%-50%, and the scanning speed at 80-150mm·s. -1 ; The preparation method of the active nitriding agent is as follows: boron nitride (BN) and ammonium acetate (NH4C2H3O2) are premixed at a mass ratio of 3:1 and pyrolyzed at 580-720°C for 100-140 min in an inert atmosphere to obtain a porous active nitriding agent. TiNx is a metastable phase of TiNx containing some subnitrogen vacancies and nitrogen vacancies.

2. The preparation method according to claim 1, characterized in that, The coating has an elastic modulus of 300-380 GPa and a bonding strength between the coating and the substrate of at least 40.3 MPa.

3. The preparation method according to claim 1, characterized in that, Fe-based amorphous powder is Fe 48 Cr 23 Mo 10 C 14 B5.

4. The application of a biomimetic corrugated layered Fe-based amorphous composite coating obtained by the preparation method according to any one of claims 1 to 3 in harsh service environments.

5. The application according to claim 4, characterized in that, Harsh service environments include marine engineering, nuclear power equipment, pumps and valves, and ships.

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