Nickel-based alloy coating reinforced by nanometer eutectic precipitate and preparation method of nickel-based alloy coating

Abstract

The invention discloses a nanometer eutectic precipitate reinforced nickel-based alloy coating and a preparation method of the nanometer eutectic precipitate reinforced nickel-based alloy coating, and belongs to the technical field of component design and structure regulation and control of laser cladding nickel-based alloy materials. A metallurgical environment beneficial to WC dissolution and carbon activation is constructed in a laser molten pool, so that WC does not exist in a final reinforced particle form any more, but participates in an in-situ reaction as a carbon source and a tungsten source, and fine and dispersed W5 (Si, B) 3 and Mo2C nano eutectic precipitates with good interface compatibility with a nickel-based matrix are synchronously generated; and therefore, active regulation and control on the size, distribution and interface structure of the carbide are realized from the aspect of a reinforced phase forming mechanism, and the problems of weak interface bonding and non-uniform structure caused by traditional additional ceramic particles are fundamentally avoided.

Description

Technical Field

[0001] This invention belongs to the technical field of composition design and microstructure control of laser cladding nickel-based alloy materials, specifically relating to a nickel-based alloy coating reinforced with nano-eutectic precipitates and its preparation method. Background Technology

[0002] For critical mechanical components operating under extreme conditions such as high temperature and abrasion, such as aero-engine blades, turbine disks, and metallurgical rolls, the surface properties directly determine the overall lifespan and reliability of the equipment. Therefore, surface engineering technologies, especially laser cladding technology, are widely used to prepare high-performance protective coatings on the surfaces of these components. Among these, nickel-based alloys, due to their excellent high-temperature resistance, oxidation resistance, and corrosion resistance, have become the preferred material system for laser cladding coatings.

[0003] However, with the increasing demands for equipment performance in modern industry, the hardness and wear resistance of traditional nickel-based alloy coatings are gradually becoming insufficient to meet the more stringent service requirements. To improve the hardness and wear resistance of coatings, the industry commonly adopts the method of directly and physically mixing high-hardness ceramic particles such as TiC and WC into nickel-based alloy powder to prepare ceramic particle-reinforced metal matrix composite coatings. Although this external particle reinforcement method can improve the surface hardness of the coating to a certain extent, it has revealed many inherent defects in the practical application of laser cladding.

[0004] Because laser cladding involves extremely high heating and cooling rates, the molten pool exists for a very short time. This often results in high-melting-point ceramic particles failing to fully dissolve in the molten pool, remaining as coarse, unmelted or slightly sintered particles in the final coating. These unmelted particles typically have poor wettability with the molten metal, leading to weak bonding between the particles and the substrate, creating a vulnerable point where microcracks easily initiate and propagate. Furthermore, due to density differences and molten pool convection, ceramic particles are prone to agglomeration or uneven distribution, resulting in an inhomogeneous coating structure, causing localized stress concentrations, and in severe cases, even directly inducing macroscopic cracks, ultimately compromising the overall toughness and service safety of the coating.

[0005] Essentially, the aforementioned problems stem from the difficulty of added ceramic particles participating in a sufficient alloying reaction under the short-time molten pool conditions of laser cladding. They remain as "exotic phases" in the coating, failing to form a stable and continuous metallurgical interface with the nickel-based matrix. To overcome the interface and distribution problems caused by these added particles, materials researchers have turned to alloying modification. For example, adding molybdenum (Mo) to powder systems has been shown to improve the wettability of the molten metal to the ceramic phase to some extent and enhance the matrix properties through solid solution strengthening. However, this type of technical solution mainly focuses on improving the state of the added particles and does not address the issues of their large size and incoherent interface from the perspective of the reinforcing phase formation mechanism.

[0006] Materials science theory indicates that nanoscale eutectic carbides, generated in situ within a material and possessing coherent or semi-coherent interfaces with the matrix, achieve more significant grain refinement and dispersion strengthening effects compared to micron-sized external particles, and exhibit higher interfacial bonding strength, making them an ideal strengthening microstructure. Chinese patent CN201811584851.X discloses a high-strength, high-toughness, fatigue-resistant nanoprecipitate-reinforced martensitic-austenitic composite steel and its preparation method, which improves the performance of the alloy steel by introducing nano-vanadium carbide into martensite. However, in the typical rapid solidification process of laser cladding, how to guide the controlled reaction of multiple alloying elements within an extremely short thermal cycle time to selectively generate nano-eutectic carbides rather than coarse or brittle phases remains a key problem that has not yet been solved by existing technologies. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a nickel-based alloy coating reinforced with nano-eutectic precipitates and a method for preparing the same, so as to solve the problems mentioned in the background art or achieve better technical effects.

[0008] To solve the aforementioned technical problems, the inventors, through practice and summarization, derived the technical solution of this invention. This invention discloses a nickel-based alloy coating reinforced with nano-eutectic precipitates comprising a composite powder. The composite powder is obtained by compounding a basic mixed powder with additive powders, wherein the additive powders account for 13.0~71.0 wt.% of the composite powder.

[0009] The basic mixed powder consists of 50-90 wt.% basic powder A and the balance basic powder B;

[0010] The base powder A is a Ni-Cr-Si-B self-fluxing alloy powder;

[0011] The base powder B is an Fe-Si-B amorphous powder;

[0012] The added powder is a mixture of WC particles and Mo powder in a certain mass ratio.

[0013] Furthermore, the composition of the Ni-Cr-Si-B self-fluxing alloy powder is as follows: C content 1.0~1.5wt.%, Cr content 10~18wt.%, Fe content 10~14wt.%, Si content 3.0~4.5wt.%, B content 0.8~3.5wt.%, Ni is the balance, and the particle size of the nickel-based powder is 200~300 mesh.

[0014] Furthermore, the composition of the Fe-Si-B amorphous powder is as follows: Si content 4.0~12.0 wt.%, B content 3.0~8.0 wt.%, Fe as the balance, and Fe-based powder particle size 350~500 mesh.

[0015] Furthermore, the proportion of WC particles in the entire composite powder system is 12.0~45.0 wt.%; and the proportion of Mo powder in the entire composite powder system is 1.0~26.0 wt.%.

[0016] Furthermore, the purity of the WC particles is 99.9%, and the particle size is 200-500 mesh; the purity of the Mo powder is 99.99%, and the particle size is 200-500 mesh.

[0017] Furthermore, the preparation method of the nickel-based alloy coating reinforced by any of the above-mentioned nano-eutectic precipitates is as follows: Mo metal powder and high surface energy Fe-Si-B amorphous alloy powder are introduced into the nickel-based alloy powder and WC particle system. During the laser cladding process, fine, dispersed W5(Si,B)3 and Mo2C nano-eutectic precipitates with good interfacial compatibility with the nickel-based matrix are generated, thereby realizing the active control of carbide size, distribution and interface structure, and improving the interfacial bonding ability and microstructure uniformity of the coating.

[0018] Furthermore, the preparation method of the nickel-based alloy coating reinforced by the nano-eutectic precipitates includes the following steps:

[0019] S1: Mix base powder A and base powder B according to the mass ratio, and then ball mill them using a planetary ball mill. The ball milling process achieves uniform coating of amorphous powder on the surface of nickel-based powder, resulting in a base mixed powder which is then taken out for later use.

[0020] S2: Mix the basic mixed powder obtained in S1 with the additive powder according to the mass ratio, and then use a planetary ball mill to ball mill the powder to uniformly disperse the WC and Mo powders in the basic mixed powder to obtain a composite powder and set it aside for later use.

[0021] S3: Using Q550 steel as the base material, cut it to the required size, remove impurities from the surface of the base material by mechanical grinding, then clean it with alcohol in an ultrasonic cleaner, blow it dry, and set it aside.

[0022] S4: Mix the composite powder obtained in S2 with alcohol and preform it uniformly on the surface of the substrate material treated in S3 to form a preform layer with a thickness of 0.5~1.5mm, and then dry it.

[0023] S5: The preformed layer in S4 is treated with laser cladding. After laser cladding, the cladding layer is naturally cooled to room temperature to obtain a nickel-based alloy coating reinforced with nano-eutectic precipitates.

[0024] Furthermore, in S1 and S2, the planetary ball mill uses cemented carbide grinding balls and a stainless steel grinding jar; during the ball milling process, the protective atmosphere is argon gas with a purity of 99.99%, the rotation speed is 300~500 rpm, and the ball milling time is 2~5 hours.

[0025] Furthermore, in step S4, the mass-to-volume ratio of the composite powder to alcohol is 10g:1.0~2.0mL.

[0026] Furthermore, in S5, the laser cladding process parameters are as follows: laser power is 2500~8500W, spot size is 1.5mm×20mm, laser scanning speed is 3.0mm / s, defocusing amount is 0~20mm; the protective gas is argon gas with a purity of 99.99% and a flow rate of 20~26L / min.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] (1) By introducing Mo metal powder and high surface energy Fe-Si-B amorphous alloy powder, the present invention constructs a metallurgical environment in the laser molten pool that is conducive to WC dissolution and carbon activation, so that WC no longer exists in the form of final reinforcing particles, but participates in the in-situ reaction as a carbon source and tungsten source, and simultaneously generates fine, dispersed W5(Si,B)3 and Mo2C nano-eutectic precipitates with good interface compatibility with nickel-based matrix. Thus, the active control of carbide size, distribution and interface structure is realized from the reinforcing phase formation mechanism, and the weak interface bonding and uneven structure caused by traditional external ceramic particles are fundamentally avoided.

[0029] (2) By changing WC from externally added reinforcing particles to in-situ reaction precursors, the present invention avoids the problems of poor bonding and high crack sensitivity of traditional WC / Ni interface, and enables the reinforcing phase to form a stable metallurgical bonding interface with the matrix.

[0030] (3) The W5(Si,B)3 generated in situ during the laser cladding process of this invention has a nanoscale eutectic distribution with Mo2C, which has higher dispersion strengthening efficiency and structure stability compared with micron-sized ceramic particles.

[0031] (4) By introducing Fe-Si-B amorphous alloy powder, the present invention improves the reaction activity of the molten pool and increases the Si and B element content of the molten pool by alloying, thereby realizing the controllability of the precipitation process of nano-eutectic carbides.

[0032] (5) By adjusting the addition ratio of WC and Mo powder, the present invention can flexibly control the quantity and size of nano-eutectic carbides, thereby achieving synergistic control of the hardness, wear resistance and toughness of the cladding layer. The process is simple and has strong engineering adaptability. Attached Figure Description

[0033] Figure 1 This is a surface morphology image of the nickel-based alloy coating reinforced with nano-eutectic precipitates prepared in Example 1 of the present invention;

[0034] Figure 2The XRD phase composition diagram of the nickel-based alloy coating reinforced with nano-eutectic precipitates prepared in Example 1 of this invention;

[0035] Figure 3 This is a transmission electron microscope (TEM) image of the nano-eutectic precipitates in the nickel-based alloy coating prepared in Example 1 of this invention.

[0036] Figure 4 The graph shows the relevant properties of the nickel-based alloy coating reinforced with nano-eutectic precipitates prepared in Example 1 of this invention. Detailed Implementation

[0037] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0038] Unless otherwise specified, the raw materials or reagents used in the following examples or comparative examples are all commercially available products or products obtained using conventional technical means.

[0039] The base powder includes two types of alloy powder, A and B. A is a Ni-Cr-Si-B self-fluxing alloy powder with the following composition: C content 1.0~1.5wt.%, Cr content 10~18wt.%, Fe content 10~14wt.%, Si content 3.0~4.5wt.%, B content 0.8~3.5wt.%, Ni is the balance, and the nickel-based powder particle size is 200~300 mesh.

[0040] B is an Fe-Si-B amorphous powder with the following composition: Si content 4.0~12.0 wt.%, B content 3.0~8.0 wt.%, Fe as the balance, and Fe-based powder particle size 350~500 mesh.

[0041] The added powder includes two types of powder, C and D. C is WC particles with a purity of 99.9% and a particle size of 200-500 mesh; D is Mo powder with a purity of 99.99% and a particle size of 200-500 mesh.

[0042] This invention uses a Vickers hardness tester and a pin-disc wear tester to test the properties of the nickel-based alloy coating reinforced with nano-eutectic precipitates.

[0043] Vickers hardness (HV) is tested using a Vickers hardness tester;

[0044] The coefficient of friction and wear loss (g / h) were tested using a pin-disc wear tester.

[0045] A method for preparing a nickel-based alloy coating reinforced with nano-eutectic precipitates, comprising the following steps:

[0046] (1) Mix base powder A and base powder B according to the mass ratio, wherein the mass fraction of base powder A is 50~90wt.%; after mixing, use a planetary ball mill for ball milling, using carbide grinding balls and stainless steel grinding jars, to achieve uniform coating of amorphous powder on the surface of nickel-based powder through ball milling, the protective atmosphere is argon gas with a purity of 99.99%, the rotation speed is 300~500rpm, the ball milling time is 2~5h, and the base mixed powder is obtained and taken out for use;

[0047] (2) Mix the basic mixed powder and the additive powder (WC powder and Mo powder) according to the mass ratio, wherein: the proportion of WC powder added in the whole powder system is 12.0~45.0 wt.%, and the proportion of Mo powder added is 1.0~26.0 wt.%; after mixing, use a planetary ball mill (the protective atmosphere is argon gas with a purity of 99.99%, using carbide grinding balls and stainless steel grinding jars, the rotation speed is 300~500 rpm, and the ball milling time is 2~5 h) to obtain the composite powder and take it out for later use; the WC and Mo powders are uniformly dispersed in the composite powder by ball milling;

[0048] (3) Using Q550 steel as the base material, cut it into 10cm×10cm×1cm size, remove oxides, oil stains, etc. on the surface of the base material by mechanical grinding, then clean it with alcohol in an ultrasonic cleaner, blow it dry, and set it aside.

[0049] (4) Mix the composite powder obtained in step (2) with alcohol (add 1.0~2.0mL of alcohol per 10g of composite powder), and uniformly pre-form it on the surface of the Q550 steel substrate after step (3) to form a pre-formed layer with a thickness of 0.5~1.5mm. Then place it in a drying oven at 150℃ for 3h.

[0050] (5) The prefabricated layer in step (4) is processed by laser cladding process. The process parameters of laser cladding are: laser power of 2500~8500W, spot size of 1.5mm×20mm, laser scanning speed of 3.0mm / s, defocusing amount of 0~20mm; the protective gas is argon gas with a purity of 99.99% and a flow rate of 20~26L / min. After laser cladding, the cladding layer is naturally cooled to room temperature to obtain a nickel-based alloy coating reinforced by nano-eutectic precipitates.

[0051] Example 1

[0052] In this embodiment, the base powder includes two types of alloy powder, A and B. A is a Ni-Cr-Si-B self-fluxing alloy powder with the following composition: C content 1.0 wt.%, Cr content 17.45 wt.%, Fe content 13.34 wt.%, Si content 4.36 wt.%, B content 3.45 wt.%, Ni is the balance, and the nickel-based powder has a particle size of 250 mesh.

[0053] B is an Fe-Si-B amorphous powder with the following composition: Si content 7.5 wt.%, B content 5.0 wt.%, Fe as the balance, and Fe-based powder particle size 400 mesh.

[0054] The added powders include two types: C and D. C is WC particles with a purity of 99.9% and a particle size of 300 mesh; D is Mo powder with a purity of 99.99% and a particle size of 400 mesh.

[0055] A method for preparing a nickel-based alloy coating reinforced with nano-eutectic precipitates, comprising the following steps:

[0056] (1) Mix base powder A and base powder B according to the mass ratio, wherein the mass fraction of base powder A is 90 wt.%; after mixing, use a planetary ball mill for ball milling, the protective atmosphere is argon gas with a purity of 99.99%, use carbide grinding balls and stainless steel grinding jar, the rotation speed is 300 rpm, the ball milling time is 3 h, and the base mixed powder is obtained and taken out for use.

[0057] (2) Mix the basic mixed powder and the additive powder (WC powder and Mo powder) according to the mass ratio, wherein: the proportion of WC powder added in the whole powder system is 20.0 wt.% and the proportion of Mo powder added is 5.0 wt.%; after mixing, use a planetary ball mill (the protective atmosphere is argon gas with a purity of 99.99%, using carbide grinding balls and stainless steel grinding jars, the rotation speed is 300 rpm, and the ball milling time is 3h) to obtain the composite powder and take it out for later use;

[0058] (3) Using Q550 steel as the base material, cut it into 10cm×10cm×1cm samples, remove oxides, oil stains, etc. on the surface of the base material by mechanical grinding, then clean it with alcohol in an ultrasonic cleaner, blow it dry, and set it aside.

[0059] (4) Mix the composite powder obtained in step (2) with alcohol (add 1.0 mL of alcohol for every 10 g of composite powder), and uniformly pre-form it on the surface of the Q550 steel substrate after step (3) to form a pre-formed layer with a thickness of 1.0 mm. Then place it in a drying oven at 150°C for 3 hours to dry.

[0060] (5) The prefabricated layer in step (4) is processed by laser cladding process. The process parameters of laser cladding are: laser power of 2500W, spot size of 1.5mm×20mm, laser scanning speed of 3.0mm / s, defocusing amount of 0mm; the protective gas is argon gas with a purity of 99.99% and a flow rate of 20L / min. After laser cladding, the cladding layer is naturally cooled to room temperature to obtain a nickel-based alloy coating reinforced by nano-eutectic precipitates.

[0061] Example 2

[0062] In this embodiment, the base powder includes two types of alloy powder, A and B. A is a Ni-Cr-Si-B self-fluxing alloy powder with the following composition: C content 1.0 wt.%, Cr content 17.45 wt.%, Fe content 13.34 wt.%, Si content 4.36 wt.%, B content 3.45 wt.%, Ni is the balance, and the nickel-based powder has a particle size of 250 mesh.

[0063] B is an Fe-Si-B amorphous powder with the following composition: Si content 7.5 wt.%, B content 5.0 wt.%, Fe as the balance, and Fe-based powder particle size 400 mesh.

[0064] The added powders include two types: C and D. C is WC particles with a purity of 99.9% and a particle size of 500 mesh; D is Mo powder with a purity of 99.99% and a particle size of 500 mesh.

[0065] A method for preparing a nickel-based alloy coating reinforced with nano-eutectic precipitates, comprising the following steps:

[0066] (1) Mix base powder A and base powder B according to the mass ratio, wherein the mass fraction of base powder A is 75 wt.%; after mixing, use a planetary ball mill for ball milling, the protective atmosphere is argon gas with a purity of 99.99%, use carbide grinding balls and stainless steel grinding jar, the rotation speed is 300 rpm, the ball milling time is 3 h, and the base mixed powder is obtained and taken out for use.

[0067] (2) The basic mixed powder and the additive powder (WC powder and Mo powder) are mixed according to the mass ratio, wherein: the proportion of WC powder added in the whole powder system is 30.0 wt.% and the proportion of Mo powder added is 8.0 wt.%; after mixing, the mixture is ball-milled using a planetary ball mill (the protective atmosphere is argon gas with a purity of 99.99%, using carbide grinding balls and stainless steel grinding jars, the rotation speed is 300 rpm, and the ball milling time is 4 h) to obtain the composite powder and take it out for later use;

[0068] (3) Using Q550 steel as the base material, cut it into 10cm×10cm×1cm samples, remove oxides, oil stains, etc. on the surface of the base material by mechanical grinding, then clean it with alcohol in an ultrasonic cleaner, blow it dry, and set it aside.

[0069] (4) Mix the composite powder obtained in step (2) with alcohol (add 1.0 mL of alcohol for every 10 g of composite powder), and uniformly pre-form it on the surface of the Q550 steel substrate after step (3) to form a pre-formed layer with a thickness of 1.0 mm. Then place it in a drying oven at 150°C for 3 hours to dry.

[0070] (5) The prefabricated layer in step (4) is processed by laser cladding process. The process parameters of laser cladding are: laser power of 4500W, spot size of 1.5mm×20mm, laser scanning speed of 3.0mm / s, defocusing amount of 20mm; the protective gas is argon gas with a purity of 99.99% and a flow rate of 26L / min. After laser cladding, the cladding layer is naturally cooled to room temperature to obtain a nickel-based alloy coating reinforced by nano-eutectic precipitates.

[0071] Example 3

[0072] In this embodiment, the base powder includes two types of alloy powder, A and B. A is a Ni-Cr-Si-B self-fluxing alloy powder with the following composition: C content 1.0 wt.%, Cr content 17.45 wt.%, Fe content 13.34 wt.%, Si content 4.36 wt.%, B content 3.45 wt.%, Ni is the balance, and the nickel-based powder has a particle size of 250 mesh.

[0073] B is an Fe-Si-B amorphous powder with the following composition: Si content 7.5 wt.%, B content 5.0 wt.%, Fe as the balance, and Fe-based powder particle size 400 mesh.

[0074] The added powders include two types: C and D. C is WC particles with a purity of 99.9% and a particle size of 300 mesh; D is Mo powder with a purity of 99.99% and a particle size of 400 mesh.

[0075] A method for preparing a nickel-based alloy coating reinforced with nano-eutectic precipitates, comprising the following steps:

[0076] (1) Mix base powder A and base powder B according to the mass ratio, wherein the mass fraction of base powder A is 60 wt.%; after mixing, use a planetary ball mill for ball milling, the protective atmosphere is argon gas with a purity of 99.99%, use carbide grinding balls and stainless steel grinding jar, the rotation speed is 300 rpm, the ball milling time is 3 h, and the base mixed powder is obtained and taken out for use.

[0077] (2) The basic mixed powder and the additive powder (WC powder and Mo powder) are mixed according to the mass ratio, wherein: the proportion of WC powder added in the whole powder system is 20.0 wt.% and the proportion of Mo powder added is 15.0 wt.%; after mixing, the mixture is ball-milled using a planetary ball mill (the protective atmosphere is argon gas with a purity of 99.99%, using carbide grinding balls and stainless steel grinding jars, the rotation speed is 300 rpm, and the ball milling time is 3h) to obtain the composite powder and take it out for later use;

[0078] (3) Using Q550 steel as the base material, cut it into 10cm×10cm×1cm samples, remove oxides, oil stains, etc. on the surface of the base material by mechanical grinding, then clean it with alcohol in an ultrasonic cleaner, blow it dry, and set it aside.

[0079] (4) Mix the composite powder obtained in step (2) with alcohol (add 1.0 mL of alcohol for every 10 g of composite powder), and uniformly pre-form it on the surface of the Q550 steel substrate after step (3) to form a pre-formed layer with a thickness of 1.0 mm. Then place it in a drying oven at 150°C for 3 hours to dry.

[0080] (5) The prefabricated layer in step (4) is processed by laser cladding process. The process parameters of laser cladding are: laser power of 8500W, spot size of 1.5mm×20mm, laser scanning speed of 3.0mm / s, defocusing amount of 20mm; the protective gas is argon gas with a purity of 99.99% and a flow rate of 26L / min. After laser cladding, the cladding layer is naturally cooled to room temperature to obtain a nickel-based alloy coating reinforced by nano-eutectic precipitates.

[0081] Example 4

[0082] The base powder includes two types of alloy powder, A and B. A is a Ni-Cr-Si-B self-fluxing alloy powder with the following composition: C content 1.0 wt.%, Cr content 17.45 wt.%, Fe content 13.34 wt.%, Si content 4.36 wt.%, B content 3.45 wt.%, Ni is the balance, and the nickel-based powder has a particle size of 250 mesh.

[0083] B is an Fe-Si-B amorphous powder with the following composition: Si content 7.5 wt.%, B content 5.0 wt.%, Fe as the balance, and Fe-based powder particle size 400 mesh.

[0084] The added powders include two types: C and D. C is WC particles with a purity of 99.9% and a particle size of 300 mesh; D is Mo powder with a purity of 99.99% and a particle size of 400 mesh.

[0085] A method for preparing a nickel-based alloy coating reinforced with nano-eutectic precipitates, comprising the following steps:

[0086] (1) Mix base powder A and base powder B according to the mass ratio, wherein the mass fraction of base powder A is 50 wt.%; after mixing, use a planetary ball mill for ball milling, using carbide grinding balls and stainless steel grinding jars, to achieve uniform coating of amorphous powder on the surface of nickel-based powder through ball milling, the protective atmosphere is argon gas with a purity of 99.99%, the rotation speed is 300 rpm, the ball milling time is 3 h, and the base mixed powder is obtained and taken out for use;

[0087] (2) The basic mixed powder and the additive powder (WC powder and Mo powder) are mixed according to the mass ratio, wherein: the proportion of WC powder added in the whole powder system is 12.0 wt.% and the proportion of Mo powder added is 26.0 wt.%; after mixing, the mixture is ball-milled using a planetary ball mill (the protective atmosphere is argon gas with a purity of 99.99%, using carbide grinding balls and stainless steel grinding jars, the rotation speed is 300 rpm, and the ball milling time is 3h) to obtain the composite powder and take it out for later use; the WC and Mo powders are uniformly dispersed in the composite powder by ball milling;

[0088] (3) Using Q550 steel as the base material, cut it into 10cm×10cm×1cm size, remove oxides, oil stains, etc. on the surface of the base material by mechanical grinding, then clean it with alcohol in an ultrasonic cleaner, blow it dry, and set it aside.

[0089] (4) Mix the composite powder obtained in step (2) with alcohol (add 1.5 mL of alcohol for every 10 g of composite powder), and uniformly pre-form it on the surface of the Q550 steel substrate after step (3) to form a pre-formed layer with a thickness of 1.0 mm. Then place it in a drying oven at 150°C for 3 hours to dry.

[0090] (5) The prefabricated layer in step (4) is processed by laser cladding process. The process parameters of laser cladding are: laser power of 5000W, spot size of 1.5mm×20mm, laser scanning speed of 3.0mm / s, defocusing amount of 20mm; the protective gas is argon gas with a purity of 99.99% and a flow rate of 24L / min. After laser cladding, the cladding layer is naturally cooled to room temperature to obtain a nickel-based alloy coating reinforced by nano-eutectic precipitates.

[0091] Example 5

[0092] The base powder includes two types of alloy powder, A and B. A is a Ni-Cr-Si-B self-fluxing alloy powder with the following composition: C content 1.0 wt.%, Cr content 17.45 wt.%, Fe content 13.34 wt.%, Si content 4.36 wt.%, B content 3.45 wt.%, Ni is the balance, and the nickel-based powder has a particle size of 250 mesh.

[0093] B is an Fe-Si-B amorphous powder with the following composition: Si content 7.5 wt.%, B content 5.0 wt.%, Fe as the balance, and Fe-based powder particle size 400 mesh.

[0094] The added powders include two types: C and D. C is WC particles with a purity of 99.9% and a particle size of 300 mesh; D is Mo powder with a purity of 99.99% and a particle size of 400 mesh.

[0095] A method for preparing a nickel-based alloy coating reinforced with nano-eutectic precipitates, comprising the following steps:

[0096] (1) Mix base powder A and base powder B according to the mass ratio, wherein the mass fraction of base powder A is 50 wt.%; after mixing, use a planetary ball mill for ball milling, using carbide grinding balls and stainless steel grinding jars, to achieve uniform coating of amorphous powder on the surface of nickel-based powder through ball milling, the protective atmosphere is argon gas with a purity of 99.99%, the rotation speed is 300 rpm, the ball milling time is 3 h, and the base mixed powder is obtained and taken out for use;

[0097] (2) The basic mixed powder and the additive powder (WC powder and Mo powder) are mixed according to the mass ratio, wherein: the proportion of WC powder added in the whole powder system is 45.0 wt.% and the proportion of Mo powder added is 1.0 wt.%; after mixing, the mixture is ball-milled using a planetary ball mill (the protective atmosphere is argon gas with a purity of 99.99%, using carbide grinding balls and stainless steel grinding jars, the rotation speed is 300 rpm, and the ball milling time is 3h) to obtain the composite powder and take it out for later use; the WC and Mo powders are uniformly dispersed in the composite powder by ball milling;

[0098] (3) Using Q550 steel as the base material, cut it into 10cm×10cm×1cm size, remove oxides, oil stains, etc. on the surface of the base material by mechanical grinding, then clean it with alcohol in an ultrasonic cleaner, blow it dry, and set it aside.

[0099] (4) Mix the composite powder obtained in step (2) with alcohol (add 2.0 mL of alcohol for every 10 g of composite powder), and uniformly pre-form it on the surface of the Q550 steel substrate after step (3) to form a pre-formed layer with a thickness of 1.0 mm. Then place it in a drying oven at 150°C for 3 hours to dry.

[0100] (5) The prefabricated layer in step (4) is processed by laser cladding process. The process parameters of laser cladding are: laser power of 3000W, spot size of 1.5mm×20mm, laser scanning speed of 3.0mm / s, defocusing amount of 20mm; the protective gas is argon gas with a purity of 99.99% and a flow rate of 24L / min. After laser cladding, the cladding layer is naturally cooled to room temperature to obtain a nickel-based alloy coating reinforced by nano-eutectic precipitates.

[0101] Comparative Example 1 (The base powder used is only a nickel-based alloy, WC powder and Mo powder are directly added, and then cladding is performed after mixing)

[0102] The base powder is a Ni-Cr-Si-B self-fluxing alloy powder with the following composition: C content 1.0 wt.%, Cr content 17.45 wt.%, Fe content 13.34 wt.%, Si content 4.36 wt.%, B content 3.45 wt.%, Ni as the balance, and the nickel-based powder particle size is 250 mesh.

[0103] The added powders are WC granules with a purity of 99.9% and a particle size of 300 mesh, and Mo powder with a purity of 99.99% and a particle size of 400 mesh.

[0104] The steps are as follows:

[0105] (1) The base powder and the additive powder are mixed according to the following mass ratio: WC powder is added at a proportion of 30.0 wt.% in the whole powder system; Mo powder is added at a proportion of 10% in the whole powder system. The composite powder is obtained by direct mechanical mixing and then taken out for use.

[0106] (2) Using Q550 steel as the base material, cut it into 10cm×10cm×1cm size, remove oxides, oil stains, etc. on the surface of the base material by mechanical grinding, then clean it with alcohol in an ultrasonic cleaner, blow it dry, and set it aside.

[0107] (3) Mix the composite powder obtained in step (1) with alcohol, add 1.0 mL of alcohol for every 10 g of composite powder, and uniformly pre-form it on the surface of the Q550 steel substrate after step (2) to form a pre-formed layer with a thickness of 1.0 mm. Then put it into a drying oven at 150°C and dry for 3 hours.

[0108] (4) The prefabricated layer in step (3) was treated using laser cladding. The laser cladding process parameters were as follows: laser power of 3500W, spot size of 1.5mm×20mm, laser scanning speed of 3.0mm / s, and defocusing amount of 20mm. The protective gas was argon gas with a purity of 99.99% and a flow rate of 24L / min. After laser cladding, the cladding layer was naturally cooled to room temperature to obtain a ceramic particle reinforced metal matrix composite coating. Microstructural observation revealed that the in-situ synthesized carbide precipitates in the cladding layer had a larger particle size. Unmelted WC particles were deposited at the bottom of the cladding layer, and cracks appeared in the cross-section of the cladding layer.

[0109] Comparative Example 2 (only WC was added to the powder, without Mo powder, and it was fused together with the base powder)

[0110] The base powder includes two types of alloy powder, A and B. A is a Ni-Cr-Si-B self-fluxing alloy powder with the following composition: C content 1.0 wt.%, Cr content 17.45 wt.%, Fe content 13.34 wt.%, Si content 4.36 wt.%, B content 3.45 wt.%, Ni is the balance, and the nickel-based powder has a particle size of 250 mesh.

[0111] B is an Fe-Si-B amorphous powder with the following composition: Si content 7.5 wt.%, B content 5.0 wt.%, Fe as the balance, and Fe-based powder particle size 400 mesh.

[0112] The added powder is WC granules with a purity of 99.9% and a particle size of 300 mesh.

[0113] The steps are as follows:

[0114] (1) Mix base powder A and base powder B directly according to the mass ratio, wherein the mass fraction of base powder A is 50 wt.%, to obtain base mixed powder and take it out for later use;

[0115] (2) The basic mixed powder and the additive powder are directly mixed according to the mass ratio, wherein: the proportion of WC powder added in the whole powder system is 30.0 wt.%; and the composite powder is obtained and taken out for use;

[0116] (3) Using Q550 steel as the base material, cut it into 10cm×10cm×1cm size, remove oxides, oil stains, etc. on the surface of the base material by mechanical grinding, then clean it with alcohol in an ultrasonic cleaner, blow it dry, and set it aside.

[0117] (4) Mix the composite powder obtained in step (2) with alcohol, add 1.0 mL of alcohol for every 10 g of composite powder, and uniformly pre-form it on the surface of the Q550 steel substrate after step (3) to form a pre-formed layer with a thickness of 1.0 mm. Then put it into a drying oven at 150°C and dry for 3 hours.

[0118] (5) The prefabricated layer in step (4) is processed by laser cladding process. The laser cladding process parameters are: laser power of 3500W, spot size of 1.5mm×20mm, laser scanning speed of 3.0mm / s, defocusing amount of 20mm; the protective gas is argon gas with a purity of 99.99% and a flow rate of 24L / min. After laser cladding, the cladding layer is naturally cooled to room temperature to obtain ceramic particle reinforced metal matrix composite coating. It is observed that uneven local enrichment of ceramic particles and a large number of unmelted WC particles are deposited at the bottom.

[0119] The hardness and wear resistance of the cladding layers prepared in Examples 1-5 and Comparative Examples 1-2 were tested respectively, and the test results are shown in Table 1 below.

[0120] Table 1. Comparison of performance test results of cladding layers prepared in Examples 1-5 and Comparative Examples 1-2

[0121]

[0122] For Table 1 and Figures 1-4 Analysis was conducted, and the surface morphology of the cladding layer in Example 1 was observed, such as... Figure 1 As shown, the nickel-based composite cladding layer is well-formed, free of cracks and porosity defects, and forms a metallurgical bond with the Q550 substrate. The phase structure of the cladding layer cross-section was examined, and the X-ray diffraction results are as follows: Figure 2 As shown, the main phase structure is γ-Ni(Fe), Cr 23 C6, Mo2C, and W5(Si,B)3. The microstructure of the cladding layer was observed using transmission electron microscopy, and the results are as follows: Figure 3 As shown, nanoscale W5(Si,B)3 and Mo2C eutectic structures can be observed. The coating properties were tested using a Vickers hardness tester and a pin-disc wear tester, and the results are as follows: Figure 4 As shown, the average Vickers hardness reaches 792.1 HV, the average coefficient of friction is 0.41, and the wear loss is 3.9 × 10⁻⁶. -3 g / h.

[0123] A comparison of Example 1 and Comparative Example 1 reveals that the inherent defect of the simple physical mixing method of adding WC particles in Comparative Example 1 stems primarily from the absence of Fe-Si-B amorphous alloy powder in the original material. In the example, during the extremely short heating-melting-solidification process of laser cladding, the amorphous alloy powder, being in a high energy state, promotes molten pool flow and the dissolution of high-melting-point WC during melting in the laser molten pool, thus providing alloying conditions for the formation of in-situ precipitated phases in the molten pool. In the comparative example, the simple mixing of powders cannot solve the density difference and weak interfacial bonding between WC particles and the metal matrix, leading to segregation and aggregation of the added WC particles during the laser cladding process.

[0124] A comparison of Example 1 and Comparative Example 2 reveals that Comparative Example 2 uses a simple physical mixing method to add WC particles to the powder system. This method lacks key carbide-forming elements such as Mo. When WC melts in the molten pool under high temperature, the released free C and W elements cannot quickly participate in the in-situ chemical reaction to form a fine precipitate phase. Ultimately, this results in a limited number of dissolved WC particles. Furthermore, during solidification, W and C elements precipitate again, forming coarse WC, which cannot form a high-density eutectic carbide precipitate phase. This leads to the final coating having a coarse, unevenly distributed, and poorly bonded reinforcing phase, severely restricting the coating performance.

[0125] After the cladding layer prepared in Example 2 was cooled to room temperature, its formability and microstructure were examined. The cladding layer showed no obvious cracks or defects and formed a tight metallurgical bond with the matrix. In the microstructure, the W5(Si,B)3 and Mo2C precipitates were dispersed at the nanoscale with good uniformity. The number and density of the nanoprecipitates were significantly improved compared to those in Example 1.

[0126] After the cladding layer prepared in Example 3 was cooled to room temperature, its macroscopic morphology and cross-sectional metallographic analysis were performed. The surface of the cladding layer was smooth and dense, without visible pores or cracks, and it exhibited a good metallurgical bonding interface with the Q550 substrate. A composite eutectic structure consisting of nanoscale W5(Si,B)3 and Mo2C carbides was formed within the cladding layer, and the quantity and density of Mo2C carbides were significantly increased compared to those in Example 2.

[0127] This invention introduces Mo metal powder and high surface energy Fe-Si-B amorphous alloy powder to create a metallurgical environment conducive to WC dissolution and carbon activation in a laser molten pool. This prevents WC from existing as final reinforcing particles, instead allowing it to participate in the in-situ reaction as a carbon and tungsten source, simultaneously generating fine, dispersed W5(Si,B)3 and Mo2C nano-eutectic precipitates with good interfacial compatibility with the nickel-based matrix. Thus, it achieves active control over the size, distribution, and interfacial structure of carbides from the perspective of the reinforcing phase formation mechanism, fundamentally avoiding the weak interfacial bonding and microstructure inhomogeneity problems caused by traditional external ceramic particles.

Claims

1. A nickel-based alloy coating reinforced with nano-eutectic precipitates, characterized in that, The product includes a composite powder, which is obtained by compounding a base powder with additive powders, wherein the additive powders account for 13.0~71.0 wt.% of the composite powder. The basic mixed powder consists of 50-90 wt.% basic powder A and the balance basic powder B; The base powder A is a Ni-Cr-Si-B self-fluxing alloy powder; The base powder B is an Fe-Si-B amorphous powder; The added powder is a mixture of WC particles and Mo powder in a certain mass ratio.

2. The nickel-based alloy coating reinforced with nano-eutectic precipitates according to claim 1, characterized in that, The composition of the Ni-Cr-Si-B self-fluxing alloy powder is as follows: C content 1.0~1.5wt.%, Cr content 10~18wt.%, Fe content 10~14wt.%, Si content 3.0~4.5wt.%, B content 0.8~3.5wt.%, Ni is the balance, and the particle size of the nickel-based powder is 200~300 mesh.

3. The nickel-based alloy coating reinforced with nano-eutectic precipitates according to claim 1, characterized in that, The composition of the Fe-Si-B amorphous powder is as follows: Si content 4.0~12.0 wt.%, B content 3.0~8.0 wt.%, Fe as the balance, and Fe-based powder particle size 350~500 mesh.

4. The nickel-based alloy coating reinforced with nano-eutectic precipitates according to claim 1, characterized in that, The proportion of WC particles in the entire composite powder system is 12.0~45.0 wt.%; the proportion of Mo powder in the entire composite powder system is 1.0~26.0 wt.%.

5. The nickel-based alloy coating reinforced with nano-eutectic precipitates according to claim 4, characterized in that, The purity of the WC particles is 99.9%, and the particle size is 200-500 mesh; the purity of the Mo powder is 99.99%, and the particle size is 200-500 mesh.

6. A method for preparing a nickel-based alloy coating reinforced with nano-eutectic precipitates as described in any one of claims 1 to 5, characterized in that, Introducing Mo metal powder and high surface energy Fe-Si-B amorphous alloy powder into a nickel-based alloy powder and WC particle system generates fine, dispersed W5(Si,B)3 and Mo2C nano-eutectic precipitates with good interfacial compatibility with the nickel-based matrix during laser cladding. This enables active control over the size, distribution, and interfacial structure of carbides, thereby improving the interfacial bonding ability and microstructure uniformity of the coating.

7. The method for preparing the nickel-based alloy coating reinforced with nano-eutectic precipitates according to claim 6, characterized in that, The steps are as follows: S1: Mix base powder A and base powder B according to the mass ratio, and then ball mill them using a planetary ball mill. The ball milling process achieves uniform coating of amorphous powder on the surface of nickel-based powder, resulting in a base mixed powder which is then taken out for later use. S2: Mix the basic mixed powder obtained in S1 with the additive powder according to the mass ratio, and then use a planetary ball mill to ball mill the powder to uniformly disperse the WC and Mo powders in the basic mixed powder to obtain a composite powder and set it aside for later use. S3: Using Q550 steel as the base material, cut it to the required size, remove impurities from the surface of the base material by mechanical grinding, then clean it with alcohol in an ultrasonic cleaner, blow it dry, and set it aside. S4: Mix the composite powder obtained in S2 with alcohol and preform it uniformly on the surface of the substrate material treated in S3 to form a preform layer with a thickness of 0.5~1.5mm, and then dry it. S5: The preformed layer in S4 is treated with laser cladding. After laser cladding, the cladding layer is naturally cooled to room temperature to obtain a nickel-based alloy coating reinforced with nano-eutectic precipitates.

8. The method for preparing the nickel-based alloy coating reinforced with nano-eutectic precipitates according to claim 7, characterized in that, In S1 and S2, the planetary ball mill uses cemented carbide grinding balls and a stainless steel grinding jar; during the ball milling process, the protective atmosphere is argon gas with a purity of 99.99%, the rotation speed is 300~500 rpm, and the ball milling time is 2~5 hours.

9. The method for preparing the nickel-based alloy coating reinforced with nano-eutectic precipitates according to claim 7, characterized in that, In step S4, the mass-to-volume ratio of the composite powder to alcohol is 10g:1.0~2.0mL.

10. The method for preparing the nickel-based alloy coating reinforced with nano-eutectic precipitates according to claim 7, characterized in that, In S5, the laser cladding process parameters are as follows: laser power is 2500~8500W, spot size is 1.5mm×20mm, laser scanning speed is 3.0mm / s, defocusing amount is 0~20mm; the protective gas is argon gas with a purity of 99.99% and a flow rate of 20~26L / min.

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