Powder metallurgy copper-based friction material for large-displacement motorcycle and preparation method of powder metallurgy copper-based friction material

Abstract

The invention relates to a powder metallurgy copper-based friction material for a large-displacement motorcycle and a preparation method of the powder metallurgy copper-based friction material, and belongs to the technical field of preparation of powder metallurgy copper-based friction materials. The surface Rockwell hardness HR15N of the powder metallurgy copper-based friction material is 50-70, the dynamic friction coefficient can reach 0.7 or above, the static friction coefficient is 0.8 or above, the wear rate is smaller than 1 * 10 <-7 > cm / (N.m), and the dynamic friction coefficient wave is smaller than 0.02. The brake can be applied to large-displacement motorcycle brakes. According to the preparation method of the powder metallurgy copper-based friction material for the large-displacement motorcycle, a pressure-free continuous sintering process is adopted, the raw materials are evenly mixed for 1-6 h according to the formula, then the mixture is pressed into a blank, high-temperature sintering is conducted in the reducing atmosphere, then machining forming is conducted, and the powder metallurgy copper-based friction material for the large-displacement motorcycle is obtained.

Description

Technical Field

[0001] This invention relates to a powder metallurgy copper-based friction material for large-displacement motorcycles and its preparation method, belonging to the technical field of powder metallurgy copper-based friction material preparation. Background Technology

[0002] Powder metallurgy friction materials are sintered using powder metallurgy methods and possess excellent friction and wear properties. Among powder metallurgy friction materials, copper-based friction materials are widely used in machining, transportation, and aerospace industries due to their superior product characteristics.

[0003] Existing powder metallurgy copper-based friction materials, mainly composed of copper, iron, tin, nickel, silicon carbide, and aluminum oxide, still suffer from problems such as low hardness and high wear rate, especially exhibiting significant fluctuations in the coefficient of friction during high-speed braking. Large-displacement motorcycles bear heavy loads and travel at high speeds, generating substantial heat. During braking, temperatures can reach or exceed 600 degrees Celsius. Therefore, friction pads need to maintain a stable coefficient of friction under high temperatures to prevent a decrease in friction due to temperature increases. Typically, friction materials are required to have a dynamic coefficient of friction of at least 0.5 and high temperature resistance, which traditional resin-based friction pads struggle to meet. The current mainstream solution is to use powder metallurgy copper-based friction materials. However, traditional powder metallurgy copper-based friction materials have a dynamic coefficient of friction below 0.4 and employ a bell-jar pressure sintering method, resulting in poor product stability and inefficient continuous production.

[0004] Rare earth elements, often referred to as "industrial MSG," play a vital role in various fields, including industry, science and technology, and modern life. Due to their unique electronic structure and chemical properties, they have wide applications in many areas. For example, the addition of heavy metals such as terbium and dysprosium can significantly improve the performance of magnetic materials, enhancing the coercivity and high-temperature resistance of neodymium-iron-boron permanent magnets; ytterbium can improve the stability and corrosion resistance of glass, while erbium can impart special optical properties to glass; the addition of rare earth elements to alloy materials can significantly improve material properties, mainly through refining grain structure, purifying melts, forming thermally stable phases, and improving corrosion resistance. Therefore, rare earth elements have a significant role in the industrial field. CN102516942B discloses an environmentally friendly friction material modified with rare earth oxides and its preparation method. By combining rare earth oxide-modified titanium-iron compounds with inorganic flame-retardant compounds, it solves the problems of unstable friction coefficients and harmful substances in existing friction materials at high temperatures, achieving an environmentally friendly brake pad material with stable friction performance and low wear rate at high temperatures. CN106051006A discloses a rare earth oxide-modified resin-based automotive brake friction material and its preparation method. By using rare earth oxides to replace metal fillers in the resin-based automotive brake friction material, combined with phenolic resin and fibers, and employing a hot-pressing process, the insufficient high-temperature performance and pollution problems of resin-based materials are solved. This results in a high-performance, metal-free rare earth oxide-modified resin-based friction material, improving the overall performance and cost-effectiveness of the friction material. These examples fully demonstrate that rare earths can improve the physical properties of resin-based friction materials, but their application in powder metallurgy copper-based friction materials has not been reported. Summary of the Invention

[0005] To address the above technical problems, this invention provides a powder metallurgy copper-based friction material with added rare earth elements, specifically a powder metallurgy copper-based friction material for large-displacement motorcycles. Its surface Rockwell hardness (HR15N) is 50-70, its dynamic friction coefficient can reach above 0.7, its static friction coefficient is above 0.8, and its wear rate is less than 1×10⁻⁶. -7 The coefficient of kinetic friction is less than 0.02 cm / (Nm). This invention is achieved through the following technical solution.

[0006] A powder metallurgy copper-based friction material for large-displacement motorcycles comprises the following components: 53-57 wt% electrolytic copper powder, 7-9 wt% reduced iron powder, 6-8 wt% atomized spherical tin powder, 3-5 wt% nickel powder, 3-5 wt% silicon carbide micro powder, 4-6 wt% graphite powder, 4-8 wt% alumina powder, 3-5 wt% fluorite powder, and 1-3 wt% rare earth oxides.

[0007] The rare earth element is at least one of the rare earth elements selected from lanthanum, cerium, praseodymium, samarium, gadolinium, terbium, dysprosium, ytterbium, erbium, and yttrium. The rare earth oxide has an oxide content (REO) ≥ 95%, a relative purity (REO / TREO) ≥ 99%, and a D50 of 3-10 μm. Rare earth oxides are usually represented by "REO," and are a general term for compounds formed by the combination of rare earth elements and oxygen elements, with content expressed as REO. The relative purity of rare earth elements is explained according to term 2.16 in the national standard GB / T 15676-2015, expressed as REO / TREO. The addition of appropriate amounts of rare earth elements can significantly improve the compatibility of the components in powder metallurgy copper-based friction materials, enhance the synergistic effect of the components, and thus improve the overall performance of the friction material. The electrolytic copper powder has a Cu content ≥ 99.9% and a sieve particle size of 200-300 mesh. Copper powder serves as the base material for copper-based friction materials, exhibiting excellent electrical and thermal conductivity. This effectively reduces heat accumulation during friction, preventing material softening or hot spot formation, making it suitable for high-load braking applications. The atomized spherical tin powder contains ≥99% Sn and has a sieve particle size of 200-300 mesh. Tin powder primarily improves the friction and wear resistance of friction materials. It increases the coefficient of friction, enhances wear resistance and durability, and improves thermal stability, maintaining good friction performance even at high temperatures. The high tin content ensures sufficient porosity while maintaining high material strength, resulting in minimal wear during friction braking. The reduced iron powder contains ≥99% Fe and has a D50 of 10-20 μm. Adding iron powder adjusts the hardness of the friction material, increases the coefficient of friction, and reduces wear. The nickel powder contains ≥99.9% Ni and has a D50 of 1-3 μm. Nickel powder can effectively improve the strength and hardness of friction materials. With increasing nickel content, the wear rate decreases and the stability of the friction coefficient increases. The silicon carbide micropowder has a SiC content ≥ 98.5% and a D50 of 5-10 μm. Silicon carbide materials are characterized by high strength, high stiffness, and high elastic modulus. They are not easily deformed under high pressure and have high compressive strength, capable of withstanding high-end stress. They also have good heat resistance and thermal conductivity. SiC, as friction-enhancing particles, is beneficial for the tribological furrowing effect, increasing the dynamic / static friction coefficient. The graphite powder is flake-shaped, with a carbon content C ≥ 99.99% and a sieve particle size of 80-100 mesh. Graphite powder is one of the most heat-resistant materials known, with a melting point of approximately 3900℃. It exhibits extremely low loss rate at ultra-high temperatures, high wear resistance, and good thermal conductivity, effectively transferring heat. This not only improves the lubricity and wear resistance of the material but also enhances its heat resistance and thermal conductivity, while reducing noise and vibration. The alumina powder has an α-Al₂O₃ content of ≥99.99%, a D50 of 30-50 nm, and a specific surface area BET = 10-20 m². 2 / g. Alumina powder can improve hardness and wear resistance, high-temperature stability, coefficient of friction and thermal conductivity in friction materials, thus extending the service life of the material. The fluorite powder contains CaF2 ≥ 98% and has a sieve particle size of 100-200 mesh. Fluorite powder can improve the coefficient of friction, wear resistance and thermal stability of friction materials, enhance the corrosion resistance of the material, and reduce friction noise.

[0008] This invention relates to a powder metallurgy copper-based friction material for large-displacement motorcycles, with a Rockwell hardness of HR15N of 50-70, a dynamic friction coefficient ≥0.7, a static friction coefficient ≥0.8, and a wear rate of less than 1×10⁻⁶. -7 With a coefficient of dynamic friction of cm / (Nm) and a fluctuation of less than 0.02, it can be applied to brakes for large-displacement motorcycles.

[0009] This invention also provides a method for preparing a powder metallurgy copper-based friction material for large-displacement motorcycles. The method employs a pressureless continuous sintering process, first mixing the raw materials according to the formula for 1-6 hours, then pressing them into a blank, sintering at high temperature under a reducing atmosphere, and finally processing and shaping to obtain the powder metallurgy copper-based friction material for large-displacement motorcycles. The formula includes 53-57 wt% electrolytic copper powder, 7-9 wt% reduced iron powder, 6-8 wt% atomized spherical tin powder, 3-5 wt% nickel powder, 3-5 wt% silicon carbide micro powder, 4-6 wt% graphite powder, 4-8 wt% alumina powder, 3-5 wt% fluorite powder, and 1-3 wt% rare earth oxides.

[0010] To ensure more uniform mixing, a gradient mixing method is employed. First, silicon carbide micropowder, graphite powder, alumina powder, fluorite powder, and rare earth oxides are mixed for 1-2 hours. Then, reduced iron powder, atomized spherical tin powder, and nickel powder are added, and the mixture is stirred again for 1-2 hours. Finally, electrolytic copper powder is added and mixed for 1-4 hours to achieve uniform mixing of all components. During mixing, atomizing an appropriate amount of anhydrous ethanol increases the wettability of the materials, which is beneficial to the mixing effect. The optimal mass ratio of anhydrous ethanol to powder is (0.1-0.5):10. After mixing, the mixture needs to be dried at 85-95℃ for 1-4 hours to remove the ethanol. Low-density pressing is used, and the density of the pressed blank is controlled at 3.5-4.0 g / cm³. 3 The material has a low elastic modulus, resulting in good fit and a high coefficient of friction during product braking. The reducing atmosphere refers to a hydrogen-nitrogen mixed atmosphere with a hydrogen content of 25-30%. The high-temperature sintering temperature is 850-950℃, the holding time is 2-5 hours, and the porosity of the sintered product is controlled at 8-10%.

[0011] The preparation method of this invention adopts a pressureless continuous sintering process, which is simple to control and operates continuously, greatly improving production efficiency and reducing production costs.

[0012] Attached image description.

[0013] Figure 1 This is a flowchart of the preparation process of the present invention.

[0014] Detailed implementation method.

[0015] To describe the invention more clearly, the following description is in conjunction with the accompanying drawings. Figure 1 The present invention will now be described in further detail.

[0016] A powder metallurgical copper-based friction material for large-displacement motorcycles comprises the following components: 53-57 wt% electrolytic copper powder, 7-9 wt% reduced iron powder, 6-8 wt% atomized spherical tin powder, 3-5 wt% nickel powder, 3-5 wt% silicon carbide micro powder, 4-6 wt% graphite powder, 4-8 wt% alumina powder, 3-5 wt% fluorite powder, and 1-3 wt% rare earth oxides. A method for preparing the powder metallurgical copper-based friction material for large-displacement motorcycles employs a pressureless continuous sintering process. First, the raw materials are mixed uniformly according to the above formula, then pressed into a blank, and sintered at high temperature without pressure under a reducing atmosphere. Finally, the blank is processed into shape to obtain the powder metallurgical copper-based friction material for large-displacement motorcycles. Specific implementation methods are as follows.

[0017] Example 1: The following powder was prepared according to the formula: 53 wt% electrolytic copper powder (Cu=99.9%, 200 mesh), 9 wt% reduced iron powder (Fe=99%, D50=10 μm), 8 wt% tin powder (Sn=99%, 300 mesh), 5 wt% nickel powder (Ni=99.9%, D50=3 μm), 5 wt% silicon carbide micro powder (SiC=98.5%, D50=5 μm), 6 wt% flake graphite powder (C=99.99%, 80 mesh), and 8 wt% alumina powder (α-Al2O3≥99.99%, D50=50 nm, BET=10 μm). 2 The following raw materials were mixed: 3 wt% fluorite powder (CaF2≥98%, 100 mesh) and 3 wt% lanthanum oxide (REO=99.2%, relative purity 99.9%, D50=8μm). The mixture was then pressed into a blank with a density of 3.5 g / cm³. 3 The billet is placed in an atmosphere pusher kiln and sintered in a 25% hydrogen-nitrogen mixed atmosphere. The temperature of the high-temperature section is 850℃. The pushing speed is controlled so that the material is kept at the high temperature for 2 hours. After exiting the kiln, it is cooled. The porosity of the sintered product is 10%. It is then processed and shaped, and the friction properties of the material are tested.

[0018] Example 2: The following powder was prepared according to the formula: 57 wt% electrolytic copper powder (Cu=99.9%, 300 mesh), 8 wt% reduced iron powder (Fe=99%, D50=20 μm), 8 wt% tin powder (Sn=99%, 200 mesh), 4 wt% nickel powder (Ni=99.9%, D50=1 μm), 5 wt% silicon carbide micro powder (SiC=98.5%, D50=10 μm), 5 wt% flake graphite powder (C=99.99%, 100 mesh), and 6 wt% alumina powder (α-Al2O3≥99.99%, D50=30 nm, BET=20 m). 2 The following raw materials were mixed: 5wt% fluorite powder (CaF2≥98%, 200 mesh) and 2wt% yttrium oxide (REO=99.2%, relative purity 99.9%, D50=3μm). The mixture was prepared by atomizing ethanol at a ratio of 0.5:10 (ethanol:powder) for 1 hour. After mixing, the mixture was dried at 85℃ for 4 hours. The resulting material was then pressed into blanks with a density of 4.0 g / cm³. 3 The billet is placed in an atmosphere pusher kiln and sintered in a 30% hydrogen-nitrogen mixed atmosphere. The temperature of the high-temperature section is 950℃. The pushing speed is controlled so that the material is kept at the high-temperature section for 3 hours. After exiting the kiln, it is cooled. The porosity of the sintered product is 8%. It is then processed and shaped, and the friction properties of the material are tested.

[0019] Example 3: The following powder was prepared according to the formula: 55 wt% electrolytic copper powder (Cu=99.9%, 250 mesh), 7 wt% reduced iron powder (Fe=99%, D50=15 μm), 8 wt% tin powder (Sn=99%, 200 mesh), 3 wt% nickel powder (Ni=99.9%, D50=2.5 ​​μm), 5 wt% silicon carbide micro powder (SiC=98.5%, D50=8 μm), 6 wt% flake graphite powder (C=99.99%, 100 mesh), and 8 wt% alumina powder (α-Al2O3≥99.99%, D50=45 nm, BET=12 m). 2 The following raw materials were mixed: 5wt% fluorite powder (CaF2≥98%, 150 mesh), 1wt% cerium oxide (REO=99.4%, relative purity 99.9%, D50=10μm), and 2% erbium oxide (REO=99.1%, relative purity 99.9%, D50=8μm). The mixture was prepared by atomizing ethanol at a ratio of 0.1:10 (ethanol:powder) for 2 hours. After mixing, the mixture was dried at 85℃ for 1 hour. The resulting material was then pressed into blanks with a density of 4.0 g / cm³. 3 The billet is placed in an atmosphere pusher kiln and sintered in a 25% hydrogen-nitrogen mixed atmosphere. The temperature of the high-temperature section is 950℃. The pushing speed is controlled so that the material is kept at the high-temperature section for 5 hours. After exiting the kiln, it is cooled. The porosity of the sintered product is 10%. It is then processed and shaped, and the material friction performance is tested.

[0020] Example 4: The following powder was prepared according to the formula: 57 wt% electrolytic copper powder (Cu=99.9%, 200 mesh), 9 wt% reduced iron powder (Fe=99%, D50=18 μm), 8 wt% tin powder (Sn=99%, 250 mesh), 5 wt% nickel powder (Ni=99.9%, D50=2 μm), 3 wt% silicon carbide micro powder (SiC=98.5%, D50=5 μm), 4 wt% flake graphite powder (C=99.99%, 100 mesh), and 8 wt% alumina powder (α-Al2O3≥99.99%, D50=40 nm, BET=15 m). 2 The mixture consists of 5wt% silicon carbide powder, 5wt% fluorite powder (CaF2≥98%, 200 mesh), and 1wt% praseodymium oxide (REO=99.2%, relative purity 99.9%, D50=4μm). First, silicon carbide micropowder, graphite powder, alumina powder, fluorite powder, and praseodymium oxide are mixed for 1 hour. Then, reduced iron powder, atomized spherical tin powder, and nickel powder are added, and the mixture is mixed again for 2 hours. Finally, electrolytic copper powder is added and mixed for 1 hour. The final mixture is then pressed into a blank with a density of 3.5 g / cm³. 3 The billet is placed in an atmosphere pusher kiln and sintered in a 30% hydrogen-nitrogen mixed atmosphere. The temperature of the high-temperature section is 900℃. The pushing speed is controlled so that the material is kept at the high-temperature section for 4 hours. After exiting the kiln, it is cooled. The porosity of the sintered product is 9%. It is then processed and shaped, and the friction properties of the material are tested.

[0021] Example 5: The following powders were prepared according to the formula: 57 wt% electrolytic copper powder (Cu=99.9%, 300 mesh), 9 wt% reduced iron powder (Fe=99%, D50=15μm), 6 wt% tin powder (Sn=99%, 250 mesh), 5 wt% nickel powder (Ni=99.9%, D50=2μm), 5 wt% silicon carbide micro powder (SiC=98.5%, D50=5μm), 6 wt% flake graphite powder (C=99.99%, 100 mesh), and 6 wt% alumina powder (α-Al2O3≥99.99%, D50=50nm, BET=10m). 2 The mixture consists of 3wt% silicon carbide powder, 3wt% fluorite powder (CaF2≥98%, 200 mesh), and 3wt% gadolinium oxide (REO=99.2%, relative purity 99.99%, D50=3μm). First, silicon carbide micro-powder, graphite powder, alumina powder, fluorite powder, and praseodymium oxide are mixed for 2 hours. Then, reduced iron powder, atomized spherical tin powder, and nickel powder are added, and the mixture is mixed again for 1 hour. Finally, electrolytic copper powder is added and mixed for 4 hours. The final mixture is then pressed into a blank with a density of 4.0 g / cm³. 3 The billet is placed in an atmosphere pusher kiln and sintered in a 25% hydrogen-nitrogen mixed atmosphere. The temperature of the high-temperature section is 950℃. The pushing speed is controlled so that the material is kept at the high-temperature section for 3 hours. After exiting the kiln, it is cooled. The porosity of the sintered product is 10%. It is then processed and shaped, and the friction properties of the material are tested.

[0022] Example 6: The following powder was prepared according to the formula: 57 wt% electrolytic copper powder (Cu=99.9%, 300 mesh), 9 wt% reduced iron powder (Fe=99%, D50=15μm), 8 wt% tin powder (Sn=99%, 250 mesh), 5 wt% nickel powder (Ni=99.9%, D50=2μm), 5 wt% silicon carbide micro powder (SiC=98.5%, D50=5μm), 6 wt% flake graphite powder (C=99.99%, 100 mesh), and 4 wt% alumina powder (α-Al2O3≥99.99%, D50=50nm, BET=10m). 2 The mixture consists of 3wt% silicon carbide powder, 3wt% fluorite powder (CaF2≥98%, 200 mesh), and 3wt% ytterbium oxide (REO=99.2%, relative purity 99.99%, D50=3μm). First, silicon carbide micro-powder, graphite powder, alumina powder, fluorite powder, and praseodymium oxide are mixed for 1 hour. Then, reduced iron powder, atomized spherical tin powder, and nickel powder are added, and the mixture is mixed again for 1 hour. Finally, electrolytic copper powder is added and mixed for 2 hours. The final mixture is then pressed into a blank with a density of 4.0 g / cm³. 3 The billet is placed in an atmosphere pusher kiln and sintered in a 25% hydrogen-nitrogen mixed atmosphere. The temperature of the high-temperature section is 950℃. The pushing speed is controlled so that the material is kept at the high-temperature section for 3 hours. After exiting the kiln, it is cooled. The porosity of the sintered product is 9%. It is then processed and shaped, and the friction properties of the material are tested.

[0023] Example 7: The following powder was prepared according to the formula: 57 wt% electrolytic copper powder (Cu=99.9%, 300 mesh), 7 wt% reduced iron powder (Fe=99%, D50=15 μm), 8 wt% tin powder (Sn=99%, 250 mesh), 5 wt% nickel powder (Ni=99.9%, D50=2 μm), 3 wt% silicon carbide micro powder (SiC=98.5%, D50=5 μm), 6 wt% flake graphite powder (C=99.99%, 100 mesh), and 8 wt% alumina powder (α-Al2O3≥99.99%, D50=50 nm, BET=10 m). 2 The mixture consists of 5wt% silicon carbide powder, 5wt% fluorite powder (CaF2≥98%, 200 mesh), and 1wt% dysprosium oxide (REO=99.2%, relative purity 99%, D50=3μm). First, silicon carbide micropowder, graphite powder, alumina powder, fluorite powder, and praseodymium oxide are mixed for 2 hours. Then, reduced iron powder, atomized spherical tin powder, and nickel powder are added, and the mixture is mixed again for 1 hour. Finally, electrolytic copper powder is added and mixed for 4 hours. The final mixture is then pressed into a blank with a density of 3.5 g / cm³. 3 The billet is placed in an atmosphere pusher kiln and sintered in a 25% hydrogen-nitrogen mixed atmosphere. The temperature of the high-temperature section is 950℃. The pushing speed is controlled so that the material is kept at the high-temperature section for 3 hours. After exiting the kiln, it is cooled. The porosity of the sintered product is 8%. It is then processed and shaped, and the friction properties of the material are tested.

[0024] Example 8: The following powder was prepared according to the formula: 57 wt% electrolytic copper powder (Cu=99.9%, 300 mesh), 9 wt% reduced iron powder (Fe=99%, D50=15μm), 8 wt% tin powder (Sn=99%, 250 mesh), 5 wt% nickel powder (Ni=99.9%, D50=2μm), 5 wt% silicon carbide micro powder (SiC=98.5%, D50=5μm), 6 wt% flake graphite powder (C=99.99%, 100 mesh), and 7 wt% alumina powder (α-Al2O3≥99.99%, D50=50nm, BET=10m). 2 The mixture consists of 3wt% silicon carbide powder (CaF2≥98%, 200 mesh), graphite powder, alumina powder, and fluorite powder. First, these are mixed for 2 hours. Then, reduced iron powder, atomized spherical tin powder, and nickel powder are added and mixed again for 2 hours. Finally, electrolytic copper powder is added and mixed for 4 hours. The final mixture is then pressed into a billet with a density of 4.0 g / cm³. 3 The billet is placed in an atmosphere pusher kiln and sintered in a 25% hydrogen-nitrogen mixed atmosphere. The temperature of the high-temperature section is 950℃. The pushing speed is controlled so that the material is kept at the high-temperature section for 3 hours. After exiting the kiln, it is cooled. The porosity of the sintered product is 10%. It is then processed and shaped, and the friction properties of the material are tested.

[0025] The molding materials prepared in the above 8 embodiments were tested for frictional properties, and the test results are shown in the table below. sample coefficient of kinetic friction static friction coefficient Fluctuation of dynamic friction coefficient Wear rate: 10⁻⁷ cm / (Nm) Rockwell hardness HR15N Example 1 0.72 0.81 <0.02 0.81 65 Example 2 0.70 0.81 <0.02 0.84 50 Example 3 0.71 0.82 <0.02 0.82 68 Example 0.73 0.85 <0.02 0.75 70 Example 4 0.71 0.80 <0.02 0.88 60 Example 5 0.72 0.83 <0.02 0.87 62 Example 6 0.70 0.81 <0.02 0.95 52 Example 7 0.74 0.84 <0.02 0.80 70 Example 8 0.61 0.70 <0.02 0.95 43

[0026] The results of the above implementation show that the friction material of the present invention has a high coefficient of friction and a low wear rate, as well as good frictional stability, and can be used in brakes for large-displacement motorcycles. Adding rare earth elements can effectively harmonize the physical properties of the components, thereby improving the overall performance of the friction material.

[0027] Obviously, the above embodiments are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation. It is neither necessary nor possible to exhaustively describe all possible implementations. Those skilled in the art will recognize that other variations or modifications can be made based on the above description, and any obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A powder metallurgy copper-based friction material for large-displacement motorcycles, characterized in that, It contains the following components: 53-57 wt% electrolytic copper powder, 7-9 wt% reduced iron powder, 6-8 wt% atomized spherical tin powder, 3-5 wt% nickel powder, 3-5 wt% silicon carbide micro powder, 4-6 wt% graphite powder, 4-8 wt% alumina powder, 3-5 wt% fluorite powder and 1-3 wt% rare earth oxides.

2. The powder metallurgy copper-based friction material according to claim 1, characterized in that, The rare earth element is at least one of the rare earth elements selected from lanthanum, cerium, praseodymium, samarium, gadolinium, terbium, dysprosium, ytterbium, erbium, and yttrium.

3. The powder metallurgy copper-based friction material according to claim 2, characterized in that, The rare earth oxide REO is ≥95%, the relative purity of rare earth REO / TREO is ≥99%, and the D50 is 3-10μm.

4. The powder metallurgy copper-based friction material according to claim 1, characterized in that, The electrolytic copper powder has a Cu content of ≥99.9%, a dendritic microstructure, and a sieve particle size of 200-300 mesh.

5. The powder metallurgy copper-based friction material according to claim 1, characterized in that, The atomized spherical tin powder has a Sn content of ≥99% and a sieve particle size of 200-300 mesh.

6. The powder metallurgy copper-based friction material according to claim 1, characterized in that, The reduced iron powder has a Fe content of ≥99% and a D50 of 10-20 μm.

7. The powder metallurgy copper-based friction material according to claim 1, characterized in that, The nickel powder has a Ni content of ≥99.9% and a D50 of 1-3 μm.

8. The powder metallurgy copper-based friction material according to claim 1, characterized in that, The silicon carbide micro powder has a SiC content of ≥98.5% and a D50 of 5-10 μm.

9. The powder metallurgy copper-based friction material according to claim 1, characterized in that, The graphite powder is in the form of flakes, with a sieve particle size of 80-100 mesh, and a carbon content of C ≥ 99.99%.

10. The powder metallurgy copper-based friction material according to claim 1, characterized in that, The alumina powder has an α-Al₂O₃ content of ≥99.99%, a D50 of 30-50 nm, and a specific surface area of ​​10-20 m². 2 / g.

11. The powder metallurgy copper-based friction material according to claim 1, characterized in that, The fluorite powder contains ≥98% CaF2 and has a sieve particle size of 100-200 mesh.

12. The powder metallurgy copper-based friction material according to any one of claims 1-11, characterized in that, The powder metallurgy copper-based friction material has a surface Rockwell hardness of HR15N of 50-70, a dynamic friction coefficient ≥0.7, a static friction coefficient ≥0.8, and a wear rate of less than 1×10⁻⁶. -7 cm / (Nm), and the kinetic friction coefficient fluctuation is less than 0.

02.

13. A method for preparing a powder metallurgy copper-based friction material for large-displacement motorcycles, characterized in that, The raw materials are mixed according to the formula for 1-6 hours, then pressed into blanks, sintered at high temperature in a reducing atmosphere, and then processed into shape to obtain powder metallurgy copper-based friction materials for large displacement motorcycles.

14. The method for preparing the powder metallurgy copper-based friction material according to claim 13, characterized in that, The formula consists of 53-57 wt% electrolytic copper powder, 7-9 wt% reduced iron powder, 6-8 wt% atomized spherical tin powder, 3-5 wt% nickel powder, 3-5 wt% silicon carbide micro powder, 4-6 wt% graphite powder, 4-8 wt% alumina powder, 3-5 wt% fluorite powder, and 1-3 wt% rare earth oxides.

15. The method for preparing the powder metallurgy copper-based friction material according to claim 13 or 14, characterized in that, The term "uniform mixing" refers to first mixing silicon carbide micro powder, graphite powder, alumina powder, fluorite powder, and rare earth oxides for 1-2 hours, then adding reduced iron powder, atomized spherical tin powder, and nickel powder, mixing again for 1-2 hours, and finally adding electrolytic copper powder and mixing for 1-6 hours.

16. The method for preparing the powder metallurgy copper-based friction material according to claim 15, characterized in that, Anhydrous ethanol is atomized and sprayed during the mixing of raw materials. The mass ratio of anhydrous ethanol to powder is (0.1-0.5):

10. After mixing, the mixture is vacuum dried at 85-95℃ for 1-4 hours.

17. The method for preparing the powder metallurgy copper-based friction material according to claim 15, characterized in that, The density of the pressed billet is 3.5-4.0 g / cm³. 3 .

18. The method for preparing the powder metallurgy copper-based friction material according to claim 15, characterized in that, The high-temperature sintering under a reducing atmosphere refers to sintering at 850-950℃ for 2-5 hours in a hydrogen-nitrogen mixed atmosphere with a hydrogen content of 25-30%.

19. The method for preparing the powder metallurgy copper-based friction material according to claim 15, characterized in that, The porosity of the sintered product is 8-10%.

Images