A method for preparing a graphene-coated niobium carbide reinforced nickel-based composite coating

Abstract

The present application belongs to the technical field of composite coating material, and relates to a preparation method of graphene-coated and niobium carbide-reinforced nickel-based composite coating. The nickel-based alloy powder is used as the main material, the niobium carbide is used as the reinforcing phase, and the G@SiO2 is used as the lubricant. After wet ball milling, laser cladding is performed; according to the volume fraction, the Ni60 is 68-72%, the G@SiO2 is 1-15%, and the balance is NbC; the G@SiO2 is obtained by forming the SiO2 shell on the graphene surface by using the non-uniform nucleation method. The preparation method can prepare the self-lubricating composite coating with good mechanical properties on the surface of the 45# steel.

Description

Technical Field

[0001] This invention belongs to the field of composite coating materials technology, and relates to a method for preparing a graphene- and niobium carbide-reinforced nickel-based composite coating. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] In the practical use of electro-hydraulic controlled hydraulic pumps and motors, the continuous reciprocating contact and relative movement between the piston rod and the inner wall easily leads to accelerated wear and adhesion of the moving components, thus affecting their service life and causing surface damage and failure. This is particularly true in high-horsepower engineering machinery, where the impact loads during operation are large, and the interaction forces between the moving components of electro-hydraulic controlled hydraulic pumps and motors are significant, easily leading to wear and damage at these points. This necessitates that each moving component not only withstand large impact loads but also possess excellent wear resistance. In the production of mechanical parts, 45# steel, due to its excellent mechanical properties and machinability, is widely used in the manufacturing of stamping dies, piston rods, and shafts such as slender shafts and stepped shafts. Therefore, there is a need for a composite material with 45# steel as the matrix and high surface wear resistance to reduce wear on the moving components of electro-hydraulic controlled hydraulic pumps and motors, thereby improving the wear resistance of these components. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a graphene- and niobium carbide-reinforced nickel-based composite coating. This method enables the fabrication of a self-lubricating composite coating with excellent mechanical properties on the surface of 45# steel.

[0005] On the one hand, a method for preparing a graphene- and niobium carbide-reinforced nickel-based composite coating is described, which uses nickel-based alloy powder (Ni60) as the main material, niobium carbide (NbC) as the reinforcing phase, and graphene-coated particles (G@SiO2) as the lubricant. The coating is formed by laser cladding after wet ball milling.

[0006] Based on volume fraction, Ni60 is 68-72%, G@SiO2 is 1-15%, and the balance is NbC;

[0007] The G@SiO2 is obtained by forming a SiO2 shell on the surface of graphene using a non-uniform nucleation method.

[0008] In the composite coating prepared by this invention, firstly, NbC, as a ceramic reinforcing phase, effectively inhibits grain growth, and its high hardness contributes to improving the microhardness of the composite coating. Secondly, the addition of G@SiO2 further promotes NbC grain refinement, and the combined effect of these two materials significantly improves the microhardness of the self-lubricating coating. Thirdly, during laser cladding, the amorphous silica shell in the G@SiO2-coated structure scatters the laser beam, reducing the focusing of the high-energy laser beam and effectively protecting the integrity of the graphene. The intact layered graphene structure can then deposit a lubricating film on the wear surface of the self-lubricating coating. This invention, through the combined effect of adding NbC and G@SiO2, ensures that the composite coating possesses both good mechanical properties and excellent self-lubricating properties.

[0009] On the other hand, a graphene- and niobium carbide-reinforced nickel-based composite coating is obtained by the above preparation method.

[0010] Thirdly, a motion component, wherein the surface of the substrate material of the motion component is provided with the above-mentioned graphene- and niobium carbide-reinforced nickel-based composite coating.

[0011] Fourthly, the application of the aforementioned moving component in engineering machinery.

[0012] The beneficial effects of this invention are as follows:

[0013] (1) This invention prepares coated graphene particles with a core-shell structure by surface coating modification of nano-graphene particles, which effectively reduces the damage to the graphene structure during laser cladding.

[0014] (2) This invention significantly enhances the mechanical properties of laser cladding composite coatings by adding NbC and G@SiO2, while achieving a good self-lubricating effect. Compared with the 45 steel substrate, the composite coating with the addition of niobium carbide (NbC) and graphene-coated particles (G@SiO2) shows a significant increase in microhardness, up to 302.7%, and a significant reduction in wear rate, down to 375.5%. Attached Figure Description

[0015] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0016] Figure 1 This is a cross-sectional SEM image of the niobium carbide and graphene-encapsulated nickel-based composite coating prepared in Example 1 of the present invention.

[0017] Figure 2The XRD pattern of the niobium carbide and graphene-encapsulated nickel-based composite coating prepared in Example 2 of this invention;

[0018] Figure 3 The image shows the microhardness of the niobium carbide and graphene-coated nickel-based composite coating prepared in Example 3 of this invention.

[0019] Figure 4 This is a comparison chart of the wear amount of the niobium carbide and graphene-coated reinforced nickel-based composite coating prepared in Example 4 of the present invention with that of the substrate material. Detailed Implementation

[0020] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] To ensure that moving components can withstand large load impacts while maintaining good wear resistance, this invention proposes a method for preparing a graphene- and niobium carbide-reinforced nickel-based composite coating.

[0023] A typical embodiment of the present invention provides a method for preparing a graphene- and niobium carbide-reinforced nickel-based composite coating, using nickel-based alloy powder (Ni60) as the main material, niobium carbide (NbC) as the reinforcing phase, and graphene-coated particles (G@SiO2) as the lubricant, which are formed by laser cladding after wet ball milling.

[0024] Based on volume fraction, Ni60 is 68-72%, G@SiO2 is 1-15%, and the balance is NbC;

[0025] The G@SiO2 is obtained by forming a SiO2 shell on the surface of graphene using a non-uniform nucleation method.

[0026] By forming a SiO2 shell on the graphene surface, the damage and burn-off of directly added graphene during the laser cladding process can be avoided.

[0027] In some embodiments, the average particle size of the Ni60 powder is 150 to 300 mesh.

[0028] In some embodiments, the average particle size of NbC is 90–110 nm.

[0029] In some embodiments, wet ball milling is carried out in an inert atmosphere. This prevents oxidation of the material during the ball milling process.

[0030] In some embodiments, the wet ball milling process is as follows: Ni60, NbC, and G@SiO2 are added to an organic solvent respectively and ultrasonically dispersed. The Ni60 dispersion, NbC dispersion, and G@SiO2 dispersion are then mixed and ultrasonically dispersed to obtain a mixture. The mixture is then ball-milled under an inert atmosphere. During ball milling, the total mass ratio of Ni60, NbC, and G@SiO2 to the mass of the milling balls is 1:9–11. The ball milling time is 36–60 hours.

[0031] The composite powder is obtained by wet ball milling and drying, then coated onto the surface of a substrate material, followed by laser cladding. In some embodiments, the composite powder after wet ball milling is coated onto the surface of a 45 steel substrate material, and then laser cladding is performed. Specifically, the thickness of the composite powder coating is 0.8–1.2 mm.

[0032] In some embodiments, the laser cladding power is 1000-2000W and the scanning speed is 500-1500mm / min.

[0033] In some embodiments, the preparation process of G@SiO2 is as follows: Nanographene is added to an organic solvent containing a dispersant and dispersed uniformly to obtain a graphene dispersion. Water and ammonia are added to the graphene dispersion to form a mixture, and the pH of the mixture is adjusted to 8-8.5 using ammonia. Tetraethyl silicate diluent is then added dropwise to the mixture, and the mixture is heated to 35-45°C for reaction. Specifically, the dispersant is polyvinylpyrrolidone. Specifically, the organic solvent is ethanol. Specifically, the mass ratio of nanographene to dispersant is 1:0.3-0.5. To ensure uniform dispersion of the graphene dispersion, dispersion is performed using ultrasound and stirring. Specifically, the mass ratio of nanographene to tetraethyl silicate is 1:15-20, preferably 1:16-17. The tetraethyl silicate diluent is diluted with ethanol.

[0034] Another embodiment of the present invention provides a graphene- and niobium carbide-reinforced nickel-based composite coating, obtained by the above preparation method.

[0035] A third embodiment of the present invention provides a motion component, wherein the surface of the substrate material of the motion component is provided with the above-mentioned graphene- and niobium carbide-reinforced nickel-based composite coating.

[0036] The fourth embodiment of the present invention provides an application of the above-mentioned moving component in engineering machinery.

[0037] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0038] In the raw material components of the following embodiments, the average particle size of Ni60 powder is 150-300 mesh; the average particle size of NbC powder is 100 nm; the average sheet size of graphene is 50-100 nm; and the thickness of graphene layers is 3-5 layers.

[0039] The preparation process of G@SiO2 in the following embodiments is as follows:

[0040] (1) Weigh 0.2g of polyvinylpyrrolidone as a dispersant and dissolve it in 200ml of anhydrous ethanol. Then weigh 0.5g of nano-graphene and add it to the anhydrous ethanol solution containing the dispersant to obtain a mixed solution. Place the mixed solution in an ultrasonic cleaner for ultrasonic vibration dispersion and stir for 1h to ensure that the graphene in the mixed solution has good dispersibility.

[0041] (2) Add distilled water and ammonia to the mixed solution to adjust the pH value to between 8 and 8.5. Measure 9 ml of tetraethyl silicate (density 0.94 g / cm³). 3 The tetraethyl silicate solution was diluted with 50 ml of anhydrous ethanol to obtain a diluted solution. This diluted solution was then slowly added dropwise to the graphene mixture at a rate of approximately 0.2 ml / min. The mixture was heated in a 40°C water bath with stirring. After the addition was complete, a suspension containing G@SiO2 was obtained.

[0042] (3) The G@SiO2 suspension was centrifuged, washed and dried to obtain G@SiO2 coated powder.

[0043] The laser cladding power in the following embodiments is 1500W; the scanning speed is 1000mm / min.

[0044] Example 1

[0045] A method for preparing a graphene- and niobium carbide-reinforced nickel-based composite coating.

[0046] The volume percentages of the composite powder components are: Ni60 70%, NbC 20%, and G@SiO2 10%. The density of Ni60 is 8.0 g / cm³. 3 The density of NbC is 7.6 g / cm³. 3 The density of G@SiO2 is 2.2 g / cm³. 3 .

[0047] According to the component ratio of the composite powder, Ni60 powder, NbC powder, and G@SiO2 powder were weighed separately and added to an appropriate amount of anhydrous ethanol. The powders were then ultrasonically dispersed and stirred for 20 min, 20 min, and 10 min respectively. The ultrasonically dispersed solutions were mixed and ultrasonically dispersed again for 10 min. To prevent oxidation during ball milling, the dispersed mixture was poured into a nitrogen-filled ball mill jar. To ensure ball milling efficiency, grinding balls at a mass ratio of 10:1 to the material were weighed and placed in the ball mill jar. The jar was then placed in a ball mill and ball milled for 48 h. After 48 h of ball milling, the mixture was poured out and placed in a vacuum drying oven at 110℃ for 24 h. After drying and sieving, a self-lubricating composite powder was obtained. The self-lubricating composite powder was uniformly coated onto the surface of a 45 steel substrate with a coating thickness of 1 mm. Then, a composite coating, i.e., a self-lubricating wear-resistant coating, was prepared by laser cladding using laser cladding equipment.

[0048] The self-lubricating wear-resistant coating prepared in this embodiment was cut into 20mm × 14mm metal pieces using wire electrical discharge machining (EDM) for easy clamping. The metal pieces were then ground to remove the corrosion and oxide layer from their surfaces. Surface scratches were removed using 220, 600, 800, 1000, and 2000 grit sandpaper, respectively. Finally, the surfaces of the metal pieces were polished using a metallographic polishing machine. Figure 1 The cross-section of the niobium carbide and graphene-coated nickel-based composite coating was observed using SEM. The niobium carbide particles in the self-lubricating wear-resistant coating were small and uniformly distributed. The addition of graphene coating significantly improved the dispersibility of niobium carbide, and the uniform dispersion of the hard phase of niobium carbide further enhanced the mechanical properties of the self-lubricating wear-resistant coating.

[0049] Example 2

[0050] A method for preparing a graphene- and niobium carbide-reinforced nickel-based composite coating.

[0051] The volume percentages of the composite powder components are 70% Ni60, 20% NbC, and 10% G@SiO2. The density of Ni60 is 8.0 g / cm³. 3 The density of NbC is 7.6 g / cm³. 3 The density of G@SiO2 is 2.2 g / cm³. 3 .

[0052] According to the component ratio of the composite powder, Ni60 powder, NbC powder, and G@SiO2 powder were weighed separately and added to an appropriate amount of anhydrous ethanol. The powders were then ultrasonically dispersed and stirred for 20 min, 20 min, and 10 min respectively. The ultrasonically dispersed solutions were mixed and ultrasonically dispersed again for 10 min. To prevent oxidation during ball milling, the dispersed mixture was poured into a nitrogen-filled ball mill jar. To ensure ball milling efficiency, grinding balls at a mass ratio of 10:1 to the material were weighed and placed in the ball mill jar. The jar was then placed in a ball mill and ball milled for 48 h. After 48 h of ball milling, the mixture was poured out and placed in a vacuum drying oven at 110℃ for 24 h. After drying and sieving, a self-lubricating composite powder was obtained. The self-lubricating composite powder was uniformly coated onto the surface of a 45 steel substrate with a coating thickness of 1 mm. Then, a composite coating, i.e., a self-lubricating wear-resistant coating, was prepared by laser cladding using laser cladding equipment.

[0053] The self-lubricating wear-resistant coating prepared in this embodiment was cut into 20mm × 14mm metal pieces using wire electrical discharge machining (EDM) for easy clamping. The metal pieces were then ground to remove the corrosion and oxide layer from their surfaces. Surface scratches were removed using 220, 600, 800, 1000, and 2000 grit sandpaper, respectively. Finally, the surfaces of the metal pieces were polished using a metallographic polishing machine. Figure 2 XRD phase analysis was performed on the self-lubricating wear-resistant coating. The main phases of the self-lubricating wear-resistant coating are niobium carbide (NbC) and chromium carbide (Cr). 23 C6 and Cr7C3), iron silicide (FeSi), iron-nickel alloy (Ni3Fe), and nickel (Ni).

[0054] Example 3

[0055] A method for preparing a graphene- and niobium carbide-reinforced nickel-based composite coating.

[0056] The volume percentages of the composite powder components are 70% Ni60, 20% NbC, and 10% G@SiO2. The density of Ni60 is 8.0 g / cm³. 3 The density of NbC is 7.6 g / cm³. 3 The density of G@SiO2 is 2.2 g / cm³. 3 .

[0057] According to the component ratio of the composite powder, Ni60 powder, NbC powder, and G@SiO2 powder were weighed separately and added to an appropriate amount of anhydrous ethanol. The powders were then ultrasonically dispersed and stirred for 20 min, 20 min, and 10 min respectively. The ultrasonically dispersed solutions were mixed and ultrasonically dispersed again for 10 min. To prevent oxidation during ball milling, the dispersed mixture was poured into a nitrogen-filled ball mill jar. To ensure ball milling efficiency, grinding balls at a mass ratio of 10:1 to the material were weighed and placed in the ball mill jar. The jar was then placed in a ball mill and ball milled for 48 h. After 48 h of ball milling, the mixture was poured out and placed in a vacuum drying oven at 110℃ for 24 h. After drying and sieving, a self-lubricating composite powder was obtained. The self-lubricating composite powder was uniformly coated onto the surface of a 45 steel substrate with a coating thickness of 1 mm. Then, a composite coating, i.e., a self-lubricating wear-resistant coating, was prepared by laser cladding using laser cladding equipment.

[0058] The self-lubricating wear-resistant coating prepared in this embodiment was cut into 20mm × 14mm metal pieces using wire electrical discharge machining (EDM) for easy clamping. The metal pieces were then ground to remove the corrosion and oxide layer from their surfaces. Surface scratches were removed using 220, 600, 800, 1000, and 2000 grit sandpaper, respectively. Finally, the surfaces of the metal pieces were polished using a metallographic polishing machine. Figure 3 Microhardness tests were performed on the self-lubricating wear-resistant coating. The microhardness of the self-lubricating wear-resistant coating showed a good trend with increasing distance from the measurement point to the surface. Within 600 μm of the surface, the microhardness exhibited good performance. Between 600 and 850 μm, the microhardness decreased sharply. Between 800 and 1000 μm, the microhardness decreased significantly but remained higher than the hardness of the 45# steel substrate. The highest microhardness of the self-lubricating wear-resistant coating was 946 HV.

[0059] Example 4

[0060] A method for preparing a graphene- and niobium carbide-reinforced nickel-based composite coating.

[0061] The volume percentages of the composite powder components are 70% Ni60, 20% NbC, and 10% G@SiO2. The density of Ni60 is 8.0 g / cm³. 3 The density of NbC is 7.6 g / cm³. 3 The density of G@SiO2 is 2.2 g / cm³. 3 .

[0062] According to the component ratio of the composite powder, Ni60 powder, NbC powder, and G@SiO2 powder were weighed separately and added to an appropriate amount of anhydrous ethanol. The powders were then ultrasonically dispersed and stirred for 20 min, 20 min, and 10 min respectively. The ultrasonically dispersed solutions were mixed and ultrasonically dispersed again for 10 min. To prevent oxidation during ball milling, the dispersed mixture was poured into a nitrogen-filled ball mill jar. To ensure ball milling efficiency, grinding balls at a mass ratio of 10:1 to the material were weighed and placed in the ball mill jar. The jar was then placed in a ball mill and ball milled for 48 h. After 48 h of ball milling, the mixture was poured out and placed in a vacuum drying oven at 110℃ for 24 h. After drying and sieving, a self-lubricating composite powder was obtained. The self-lubricating composite powder was uniformly coated onto the surface of a 45 steel substrate with a coating thickness of 1 mm. Then, a composite coating, i.e., a self-lubricating wear-resistant coating, was prepared by laser cladding using laser cladding equipment.

[0063] The self-lubricating wear-resistant coating prepared in this embodiment was cut into 20mm × 14mm metal pieces using wire electrical discharge machining (EDM) for easy clamping. The metal pieces were then ground to remove the corrosion and oxide layer from their surfaces. Surface scratches were removed using 220, 600, 800, 1000, and 2000 grit sandpaper, respectively. Finally, the surfaces of the metal pieces were polished using a metallographic polishing machine. Figure 4 Wear resistance tests were conducted on 45 steel and self-lubricating wear-resistant coating materials using an MDW-02 high-speed reciprocating friction and wear testing machine. The results showed that the wear amount of the self-lubricating wear-resistant coating was 2.45 × 10⁻⁶. 6 (μm 3 Compared to the 45 steel matrix material 11.65×10 6 (μm 3 The wear rate was reduced significantly by 375.5%.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for producing a graphene-coated and niobium carbide-reinforced nickel-based composite coating, characterized by, Ni60 powder is used as the main material, NbC is used as the reinforcing phase, and G@SiO2 is used as the lubricant, and the laser cladding is formed after wet ball milling; According to the volume fraction, the content of Ni60 is 68-72%, the content of G@SiO2 is 1-15%, and the balance is NbC; The G@SiO2 is obtained by forming a SiO2 shell on the surface of graphene using a heterogeneous nucleation method.

2. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 1, characterized in that, The average particle size of the Ni60 powder is 150-300 mesh. Or, the average particle size of the NbC is 90-110 nm.

3. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 1, characterized in that, The wet ball milling is carried out in an inert atmosphere.

4. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 1, characterized in that, The process of wet ball milling is as follows: Ni60, NbC and G@SiO2 are respectively added into an organic solvent, ultrasonic dispersion is carried out, then the Ni60 dispersion, the NbC dispersion and the G@SiO2 dispersion are mixed, ultrasonic dispersion is carried out to obtain a mixed liquid, and then the mixed liquid is ball milled in an inert atmosphere.

5. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 4, characterized in that, During the ball milling, the mass ratio of the total mass of Ni60, NbC and G@SiO2 to the mass of the grinding balls is 1:9-11.

6. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 4, characterized in that, The ball milling time is 36-60 h.

7. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 1, characterized in that, After the wet ball milling, the composite powder is coated on the surface of the 45 steel base material, and then laser cladding is carried out.

8. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 7, characterized in that, The thickness of the composite powder coating is 0.8-1.2 mm.

9. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 1, characterized in that, In the laser cladding, the laser cladding power is 1000-2000 W, and the scanning speed is 500-1500 mm / min.

10. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 1, characterized in that, The preparation process of G@SiO2 is as follows: nano-graphene is added into an organic solvent containing a dispersant to obtain a graphene dispersion liquid, water and ammonia are added to the graphene dispersion liquid to prepare a mixed liquid, and the pH of the mixed liquid is adjusted to 8-8.5 by using ammonia; and then tetraethyl orthosilicate diluent is added dropwise into the mixed liquid, and the reaction is carried out by heating to 35-45 ℃.

11. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 10, characterized in that, The dispersant is polyvinylpyrrolidone.

12. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 10, characterized in that, The organic solvent is ethanol.

13. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 10, characterized in that, The mass ratio of nano-graphene to dispersant is 1:0.3-0.

5.

14. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 10, characterized in that, The mass ratio of nano-graphene to tetraethyl orthosilicate is 1:15-20.

15. The method for preparing the graphene- and niobium carbide-reinforced nickel-based composite coating as described in claim 10, characterized in that, The mass ratio of nano-graphene to tetraethyl orthosilicate is 1:16-17.

16. A coated graphene and niobium carbide reinforced nickel-based composite coating, characterized by, The preparation method is obtained by any one of claims 1-15.

17. A moving member characterized by, The base material surface of the moving member is provided with the coated graphene and niobium carbide reinforced nickel-based composite coating layer.

18. Use of the moving member of claim 17 in an engineering machine.

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