A nano-alloy composite material for self-repairing of metal friction pair surfaces and a preparation method and application thereof

Abstract

The present application relates to metal wear self-repairing material technical field, specifically relates to a kind of for the surface self-repairing of metal friction pair nano-alloy composite material and its preparation method and application.The method includes the following steps: (1) nanometer boron carbide powder is dispersed in oxidizing agent, control the pH value of mixture is 0.5~3, stirring reaction at room temperature, washing to neutral, then vacuum drying, and the modified boron carbide powder of obtaining;(2) iron-based alloy powder, modified boron carbide powder, nanometer graphite powder are mixed, add ethanol as dispersing medium, ultrasonic dispersion, vacuum drying, and the composite material powder of obtaining;(3) the composite material powder is placed into high-energy ball mill and is ball milled, and the nano-alloy composite material of obtaining.The preparation method of the present application is simple, efficient and fast, the composite material particle size prepared is controllable, and the uniformity is good, the hardness of the composite material prepared is high, the wear resistance is strong, and the adsorption lubricity is good.

Description

Technical Field

[0001] The present invention relates to the technical field of metal wear self-repairing materials, and in particular to a nano alloy composite material for self-repairing the surface of a metal friction pair, and a preparation method and application thereof. Background Art

[0002] During the continuous operation of mechanical equipment, the wear of vulnerable parts often gradually intensifies due to the various loads and friction they bear over a long period of time, until they exceed their service limits and need to be scrapped and replaced. This phenomenon is one of the major reasons for equipment failure, affecting production efficiency and increasing maintenance costs. Traditional repair methods such as welding and spraying, while able to repair worn areas to a certain extent, have many limitations. For example, welding may cause changes in the material properties of the heat-affected zone, while spraying may cause peeling and other problems due to insufficient bonding strength between the coating and the substrate. More importantly, these traditional repair methods often require the dismantling of the mechanical equipment, which not only increases maintenance costs but also prolongs equipment downtime, thereby affecting the continuous operation of the production line.

[0003] Metal wear self-repair technology offers a new approach to addressing component wear. This technology involves adding self-repairing materials to lubricants or greases, creating a stable, dispersed colloidal system. Under the influence of friction and frictional heat, the self-repairing materials chemically react or physically deposit on the worn surface, forming a self-repairing protective layer. This layer not only fills the pits and cracks caused by wear but also restores the surface topography and performance of the component to a certain extent, enabling self-repair of the worn area.

[0004] In recent years, with the development of nanomaterials and composite materials, metal wear self-repair technology has made significant progress. Research has shown that various nanoscale self-repair agents, as lubricant additives, possess significant self-repair capabilities and demonstrate the potential to achieve "zero wear." However, existing repair materials, such as micron-sized metal powders or nano-ceramic particles, tend to agglomerate in lubricants, resulting in uneven dispersion and difficulty forming a good metallurgical bond with the friction pair surfaces. When the friction environment exceeds a certain threshold, the protective layer is prone to shedding and failure, potentially adversely affecting the mechanical equipment.

[0005] Therefore, developing a new self-healing agent is of great significance to improving the performance of the self-healing protective layer. Summary of the Invention

[0006] The present invention aims to provide a nano-alloy composite material for self-repairing metal friction pair surfaces, as well as its preparation method and application. By introducing a composite system of iron-based alloy, boron carbide, and graphite between the friction pairs, cracks and unevenness are filled, rapidly increasing the contact surface between the friction pairs. Under the influence of friction and frictional heat, the composite material and the friction pair material undergo interfacial adsorption, forming a thin film that reduces frictional resistance and improves the anti-friction and anti-wear properties of the lubricant, thereby achieving self-repair of wear.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows:

[0008] A first aspect of the present invention provides a method for preparing a nano-alloy composite material for self-repairing the surface of a metal friction pair, the method comprising the following steps:

[0009] (1) dispersing nano boron carbide powder in an oxidant, controlling the pH value of the mixture to be 0.5-3, stirring the mixture at room temperature, washing with water until neutral, and then vacuum drying to obtain modified boron carbide powder;

[0010] (2) mixing iron-based alloy powder, modified boron carbide powder, and nanographite powder, adding ethanol as a dispersion medium, ultrasonically dispersing, and vacuum drying to obtain a composite material powder;

[0011] (3) The composite material powder is placed in a high-energy ball mill for ball milling to obtain the nano alloy composite material.

[0012] In the above technical solution, further, the iron-based alloy is selected from one of Fe-Cr-C alloy and FeNi alloy.

[0013] In the above technical solution, further, the mass of the nano boron carbide powder accounts for 5% to 15% of the total mass of the boron carbide powder and the iron-based alloy powder; and the mass ratio of the nano graphite powder to the nano boron carbide powder is 2:5.

[0014] In the above technical solution, further, in step (1), the oxidant is concentrated sulfuric acid or concentrated nitric acid.

[0015] In the above technical solution, further, in the step (1), the stirring time is 1 to 4 hours; and the vacuum drying temperature is 40 to 60°C.

[0016] In the above technical solution, further, in the step (2), the ultrasonic power is 200-300W, the processing time is 20-30 minutes; and the vacuum drying temperature is 40-60°C.

[0017] In the above technical solution, further, in the step (3), the ball milling time is 12 to 24 hours, the ball-to-material ratio is 10:1, and the rotation speed is 200 to 300 rpm.

[0018] A second aspect of the present invention provides a nano alloy composite material for self-repairing the surface of a metal friction pair, which is obtained by the above-mentioned preparation method.

[0019] A third aspect of the present invention provides a lubricating oil, to which the aforementioned nano alloy composite material is added, and the content of the composite material in the lubricating oil is 0.01 wt% to 1 wt%.

[0020] The beneficial effects of the present invention are:

[0021] 1. The preparation method of the present invention is simple, efficient and rapid. The particle size of the composite material obtained is controllable and uniform. The composite material obtained has high hardness, strong wear resistance, good adsorption and lubricity, and forms a stably dispersed colloidal system in various lubricating oils.

[0022] 2. The present invention modifies boron carbide to modify its surface with hydroxyl functional groups, thereby increasing the polarity of the boron carbide surface and causing it to interact more strongly with polar molecules in the lubricating oil. This reduces the aggregation of boron carbides, thereby improving their dispersibility in the lubricating oil, and enhances the interfacial adsorption strength.

[0023] 3. The present invention utilizes graphite powder and boron carbide to form a stable lubricating film during the friction process, thereby reducing direct contact between the friction pairs and lowering the coefficient of friction. Specifically, boron carbide acts as a catalyst to accelerate the graphitization process, thereby forming a graphite-like lubricating film at the friction interface, improving its stability and durability. Furthermore, the combination of graphite powder and boron carbide promotes crack deflection and a bridging effect, thereby enhancing interfacial bonding strength.

[0024] 4. The composite material of the present invention does not chemically react with lubricating oil, does not change the viscosity and properties of lubricating oil, and has no toxic side effects, thereby ensuring the safety and stability of the composite material in practical applications. DETAILED DESCRIPTION

[0025] The following examples may enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0026] In the following examples, the particle size of the iron-based alloy powder is 1 to 10 μm, the Fe-Cr-C alloy powder used is FeCr55C6.0 alloy powder, and the FeNi alloy is FeNi36; the nano-boron carbide powder is purchased from Zhejiang Yamei Technology Co., Ltd., with a particle size of 60 nm and a purity of 99.9%; the nano-graphite powder is purchased from Shanghai Merrill Biochemical Technology Co., Ltd., with a particle size of <400 nm and a purity of 99.95%.

[0027] Example 1

[0028] A method for preparing a nano-alloy composite material for self-repairing the surface of a metal friction pair comprises the following steps:

[0029] (1) dispersing nano boron carbide powder in concentrated nitric acid, controlling the pH value of the mixture to 0.5-3, stirring and reacting at room temperature for 2 hours, washing with water until neutral, and then vacuum drying at 60° C. to obtain modified boron carbide powder;

[0030] (2) FeCr55C6.0 alloy powder was weighed so that the mass of boron carbide powder accounted for 5% of the total mass of boron carbide powder and iron-based alloy powder, and graphite powder was weighed so that the mass ratio of nano-graphite powder to nano-boron carbide powder was 2:5. The FeCr55C6.0 alloy powder, modified boron carbide powder, and graphite powder were mixed, ethanol was added as a dispersion medium, and ultrasonic treatment was performed at 200W for 30 minutes. Subsequently, vacuum drying was performed at 60°C to remove ethanol to obtain a composite material powder;

[0031] (3) The composite material powder was placed in a high-energy ball mill for ball milling for 24 hours, with a ball-to-material ratio of 10:1 and a rotation speed of 200 rpm to obtain a nano-alloy composite material.

[0032] Example 2

[0033] A method for preparing a nano-alloy composite material for self-repairing the surface of a metal friction pair comprises the following steps:

[0034] (1) dispersing nano boron carbide powder in concentrated nitric acid, controlling the pH value of the mixture to 0.5-3, stirring and reacting at room temperature for 2 hours, washing with water until neutral, and then vacuum drying at 60° C. to obtain modified boron carbide powder;

[0035] (2) FeCr55C6.0 alloy powder was weighed so that the mass of boron carbide powder accounted for 10% of the total mass of boron carbide powder and iron-based alloy powder, and graphite powder was weighed so that the mass ratio of nano-graphite powder to nano-boron carbide powder was 2:5. The FeCr55C6.0 alloy powder, modified boron carbide powder, and graphite powder were mixed, ethanol was added as a dispersion medium, and ultrasonic treatment was performed at 200W for 30 minutes. Then, vacuum drying was performed at 60°C to remove ethanol to obtain a composite material powder;

[0036] (3) The composite material powder was placed in a high-energy ball mill for ball milling for 24 hours, with a ball-to-material ratio of 10:1 and a rotation speed of 200 rpm to obtain a nano-alloy composite material.

[0037] Example 3

[0038] A method for preparing a nano-alloy composite material for self-repairing the surface of a metal friction pair comprises the following steps:

[0039] (1) dispersing nano boron carbide powder in concentrated nitric acid, controlling the pH value of the mixture to 0.5-3, stirring and reacting at room temperature for 2 hours, washing with water until neutral, and then vacuum drying at 60° C. to obtain modified boron carbide powder;

[0040] (2) FeCr55C6.0 alloy powder was weighed so that the mass of boron carbide powder accounted for 15% of the total mass of boron carbide powder and iron-based alloy powder, and graphite powder was weighed so that the mass ratio of nano-graphite powder to nano-boron carbide powder was 2:5. The FeCr55C6.0 alloy powder, modified boron carbide powder, and graphite powder were mixed, ethanol was added as a dispersion medium, and ultrasonic treatment was performed at 200 W for 30 minutes. Then, vacuum drying was performed at 60° C. to remove ethanol, thereby obtaining a composite material powder;

[0041] (3) The composite material powder was placed in a high-energy ball mill for ball milling for 24 hours, with a ball-to-material ratio of 10:1 and a rotation speed of 200 rpm to obtain a nano-alloy composite material.

[0042] Example 4

[0043] A method for preparing a nano-alloy composite material for self-repairing the surface of a metal friction pair comprises the following steps:

[0044] (1) dispersing nano boron carbide powder in concentrated sulfuric acid, controlling the pH value of the mixture to 0.5-3, stirring and reacting at room temperature for 2 hours, washing with water until neutral, and then vacuum drying at 60°C to obtain modified boron carbide powder;

[0045] (2) FeNi36 alloy powder was weighed so that the mass of boron carbide powder accounted for 10% of the total mass of boron carbide powder and iron-based alloy powder, and graphite powder was weighed so that the mass ratio of nano-graphite powder to nano-boron carbide powder was 2:5. The FeNi36 alloy powder, modified boron carbide powder, and graphite powder were mixed, ethanol was added as a dispersion medium, and ultrasonic treatment was performed at 300W for 20 minutes. Then, vacuum drying was performed at 60°C to remove ethanol to obtain a composite material powder;

[0046] (3) The composite material powder was placed in a high-energy ball mill for ball milling for 12 hours, with a ball-to-material ratio of 10:1 and a rotation speed of 300 rpm to obtain a nano-alloy composite material.

[0047] Comparative Example 1

[0048] A method for preparing a nano-alloy composite material for self-repairing the surface of a metal friction pair comprises the following steps:

[0049] (1) FeCr55C6.0 alloy powder was weighed so that the mass of boron carbide powder accounted for 10% of the total mass of boron carbide powder and iron-based alloy powder, and graphite powder was weighed so that the mass ratio of nano-graphite powder to nano-boron carbide powder was 2:5. The FeCr55C6.0 alloy powder, boron carbide powder, and graphite powder were mixed, ethanol was added as a dispersion medium, and ultrasonic treatment was performed at 200 W for 30 minutes. Subsequently, vacuum drying was performed at 60° C. to remove ethanol, thereby obtaining a composite material powder;

[0050] (2) The composite material powder was placed in a high-energy ball mill for ball milling for 24 hours, with a ball-to-material ratio of 10:1 and a rotation speed of 200 rpm to obtain a nano-alloy composite material.

[0051] Comparative Example 2

[0052] A method for preparing a nano-alloy composite material for self-repairing the surface of a metal friction pair comprises the following steps:

[0053] (1) dispersing nano boron carbide powder in concentrated nitric acid, controlling the pH value of the mixture to 0.5-3, stirring and reacting at room temperature for 2 hours, washing with water until neutral, and then vacuum drying at 60° C. to obtain modified boron carbide powder;

[0054] (2) FeCr55C6.0 alloy powder was weighed so that the mass of the boron carbide powder accounted for 10% of the total mass of the boron carbide powder and the iron-based alloy powder, the FeCr55C6.0 alloy powder and the modified boron carbide powder were mixed, ethanol was added as a dispersion medium, and ultrasonic treatment was performed at 200 W for 30 minutes, followed by vacuum drying at 60° C. to remove the ethanol, thereby obtaining a composite material powder;

[0055] (3) The composite material powder was placed in a high-energy ball mill for ball milling for 24 hours, with a ball-to-material ratio of 10:1 and a rotation speed of 200 rpm to obtain a nano-alloy composite material.

[0056] Test Example 1

[0057] Wear performance tests were conducted using a Falex friction and wear tester with a load range of 0.1 to 0.44 MPa. Bearing specimens were made of 45# steel. SD / CC grade 15W40 universal gasoline / diesel oil was used as lubricant. The nano-alloy composite materials prepared in Examples 1-4 and Comparative Examples 1-2 were added to the oil at a concentration of 0.01 wt%. After a 24-hour bearing simulation test, self-healing films formed on the 45# steel surfaces. Table 1 shows the nanohardness of the self-healing films on the 45# steel specimens after the test.

[0058] Table 1

[0059] Example Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Nano-hardness / HV 0.2mN ]] 1257.7 1340.5 1325.6 1322.0 901.1 998.5

[0060] The lubricating oil without the composite material added was used as a control group. Table 2 shows the surface roughness of the shaft samples of Examples 1-4 and Comparative Examples 1-2.

[0061] Table 2

[0062] Example Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Control Surface roughness Ra / pm 0.3577 0.2358 0.3325 0.3017 0.5013 0.5220 0.5422

[0063] After 500 hours of testing, the lubricant was removed and drained completely, leaving the upper and lower specimens in a boundary lubrication contact state. The testing machine was restarted, and the change in the friction coefficient was recorded, as shown in Table 3.

[0064] Table 3

[0065] Example Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Friction coefficient 0.010 0.0057 0.0087 0.0088 0.054 0.079

[0066] Application Example 1

[0067] The composite material prepared in Example 2 was added to the lubricant of a commercial vehicle at a concentration of 0.3 wt% for testing. Prior to the test, the vehicle had driven 80,000 kilometers. The engine exhibited high noise and vibration, and the lubricant had turned black. Before refueling, the engine cylinder pressure was tested and found to be 50% below the standard. After cleaning the engine cylinder of crude oil sludge and replacing the lubricant, the composite material from Example 2 was added. After 30 minutes of operation, engine noise and vibration were significantly reduced, power was increased, and the blue smoke in the exhaust was significantly reduced. After driving 1,000 kilometers, the engine cylinder pressure increased by 33.8%.

[0068] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the scope defined in the claims. Other variations or modifications may be made based on the above description. Obvious variations or modifications derived therefrom shall remain within the scope of protection of the present invention.

Claims

1. A method for preparing a nano alloy composite material for self-repairing of metal friction pair surfaces, characterized in that: The method comprises the following steps: (1) Dispersing nano-boron carbide powder in an oxidant, controlling the pH value of the mixture to be 0.5-3, stirring the mixture at room temperature, washing with water until neutral, and then vacuum drying to obtain modified boron carbide powder; (2) Mixing iron-based alloy powder, modified boron carbide powder, and nanographite powder, adding ethanol as a dispersion medium, ultrasonically dispersing, and vacuum drying to obtain composite material powder; (3) placing the composite material powder into a high-energy ball mill for ball milling to obtain the nano-alloy composite material; The iron-based alloy is selected from one of Fe-Cr-C alloy and FeNi alloy; The mass of the nano boron carbide powder accounts for 5% to 15% of the total mass of the nano boron carbide powder and the iron-based alloy powder; The mass ratio of the nano-graphite powder to the nano-boron carbide powder is 2:5; In the step (1), the oxidant is concentrated sulfuric acid or concentrated nitric acid.

2. The preparation method according to claim 1, characterized in that In the step (1), the stirring time is 1 to 4 hours; The vacuum drying temperature is 40~60℃.

3. The preparation method according to claim 1, characterized in that In step (2), the ultrasonic power is 200-300W and the treatment time is 20-30 minutes; The vacuum drying temperature is 40~60℃.

4. The preparation method according to claim 1, characterized in that In the step (3), the ball milling time is 12 to 24 hours, the ball-to-material ratio is 10:1, and the rotation speed is 200 to 300 rpm.

5. A nano alloy composite material for self-repair of metal friction pair surfaces obtained by the preparation method according to any one of claims 1 to 4.

6. A lubricating oil, characterized in that: The nano alloy composite material according to claim 5 is added to the lubricating oil, and the content of the nano alloy composite material in the lubricating oil is 0.01 wt % to 1 wt %.