1、铜-石墨材料摩擦学行为的研究AbstractCopper-graphite composite material has been widely used in sliding bearing because of its excellent properties of wear resistance and self-lubrication. In this paper, the frictional behavior of copper-graphite composite material was studied using a pin-on-disk wear test system.
2、 The effects of sliding velocity, normal load and graphite content on the friction coefficient and wear rate were investigated. The results showed that the friction coefficient decreased with the increase of sliding velocity and graphite content, while the wear rate increased. With the increase of n
3、ormal load, the friction coefficient and wear rate both increased. The wear morphology and mechanism were also studied. The results showed that the wear mechanism of the copper-graphite composite material under high normal load was mainly characterized by the abrasive wear and adhesion wear.Introduc
4、tionIn recent years, copper-graphite composite material has been widely used in high-speed, high-temperature and high-pressure environments due to its excellent properties of wear resistance and self-lubrication 1-2. The self-lubricating properties of the material are due to the excellent lubricity
5、of graphite, which can form a solid lubricating film on the surface of the material during the sliding process, reducing the friction and wear of the material3-4. The properties of the copper-graphite composite material are closely related to the content of graphite in the material. Therefore, the s
6、tudy of the tribological properties of copper-graphite composite material is of great theoretical and practical significance.MethodologyIn this study, the frictional behavior of copper-graphite composite material was investigated using a pin-on-disk wear test system. The material used in the experim
7、ent was copper-graphite composite material with different graphite contents (5 wt%, 10 wt%, and 15 wt%). The friction coefficient and wear rate were measured under different sliding velocities (0.1, 0.2, and 0.3 m/s), normal loads (50, 100, and 150 N), and sliding distances (1000, 2000, and 3000 m).
8、Results and discussionThe effects of different experimental parameters on the friction coefficient and wear rate of copper-graphite composite material are shown in Fig. 1 and Fig. 2.Fig. 1 shows the variation of the friction coefficient with sliding velocity and graphite content. It can be seen that
9、 the friction coefficient decreased with the increase of sliding velocity and graphite content. This is because with the increase of sliding velocity, the thermal effect generated by the frictional heat increases, which promotes the formation and maintenance of graphite lubrication film on the surfa
10、ce of the material. At the same time, the increase of graphite content can also increase the formation of the lubricating film, so as to reduce the friction coefficient.Fig. 2 shows the variation of the wear rate with sliding velocity and graphite content. It can be seen that the wear rate increased
11、 with the increase of sliding velocity and graphite content. This is because with the increase of sliding velocity, the thermal effect generated by the frictional heat increases, which leads to increase the mechanical and thermal stresses of the material, promoting the removal of the graphite lubric
12、ation film on the surface of the material, and then increasing the wear rate. At the same time, the increase of graphite content can also result in the increase of the brittleness of material, resulting in the increase of wear rate.Fig. 3 shows the variation of the friction coefficient and wear rate
13、 with normal load. It can be seen that both the friction coefficient and wear rate increased with the increase of normal load. This is mainly because with the increase of normal load, the mechanical and thermal stresses of the material increase, which promotes the removal of the graphite lubrication
14、 film on the surface of the material and then increases the friction coefficient and wear rate.The wear morphologies of copper-graphite composite material under different experimental conditions are shown in Fig. 4. Under low normal load, the wear mechanism of the material is mainly characterized by
15、 abrasive wear of the copper particles and graphite flakes. With the increase of normal load, the wear mechanism of the material changes to adhesion wear and abrasive wear.ConclusionIn this study, the tribological behavior of copper-graphite composite material was studied using a pin-on-disk wear te
16、st system. The effects of sliding velocity, normal load and graphite content on the friction coefficient and wear rate were investigated. The results showed that the friction coefficient decreased with the increase of sliding velocity and graphite content, while the wear rate increased. With the inc
17、rease of normal load, both the friction coefficient and wear rate increased. The study of the wear mechanism showed that the wear mechanism of the copper-graphite composite material under high normal load was mainly characterized by abrasive wear and adhesion wear. The results of this study can prov
18、ide a theoretical basis for the selection and application of copper-graphite composite material in sliding bearings.In addition to the tribological behavior of copper-graphite composite material, its mechanical properties are also important for its application in sliding bearings. Studies have shown
19、 that the addition of graphite can increase the hardness and elastic modulus of the material, while reducing the ductility and impact toughness 5-6. Therefore, the proportion of graphite in the material needs to be carefully selected according to the specific application environment.Moreover, the we
20、ar behavior of copper-graphite composite material is affected by various parameters such as temperature, humidity, and surface roughness. Therefore, these factors should also be considered when selecting and applying the material.In recent years, there have been many studies on the modification of c
21、opper-graphite composite material to improve its tribological properties. For example, the addition of solid lubricants such as MoS2 and PTFE can further reduce the friction coefficient and wear rate 7-8. The use of porous materials and surface modification techniques can also effectively improve th
22、e self-lubricating performance of the material 9-10.In summary, the study of the tribological behavior of copper-graphite composite material is of great practical significance for its application in sliding bearings. Through detailed investigation and analysis of its tribological behavior and wear m
23、echanism, the application range of the material can be further expanded, and its performance can be further improved.In addition to the above-mentioned factors, the microstructure of the material also plays an important role in its tribological behavior. The grain size, distribution and orientation
24、of the copper matrix can affect the contact pressure, deformation and wear resistance of the material 11-12. Moreover, the uniform dispersion of graphite particles in the copper matrix is crucial for the formation of a stable and effective lubricating film on the surface.Furthermore, the lubrication
25、 regime of sliding bearings is an important consideration when selecting and applying copper-graphite composite material. Under boundary lubrication conditions, where the lubricant film is insufficient, the material is prone to adhesive wear and seizure 13-14. However, under fluid lubrication condit
26、ions, where the lubricant film is sufficient, the material can exhibit excellent anti-wear and anti-friction properties due to the formation of a boundary layer of graphite particles.In terms of practical application, copper-graphite composite material has been widely used in various fields such as
27、automotive industry, machinery, and aerospace. For example, it has been applied in engine bearings, thrust washers, and bushings to reduce friction, noise and wear 15-16. Furthermore, the use of copper-graphite composite material can also contribute to energy saving, environmental protection, and ec
28、onomic benefits by extending the service life of sliding bearings and reducing maintenance costs.In conclusion, by understanding the tribological behavior of copper-graphite composite material, we can maximize its potential in various fields and applications. Further research and development are nee
29、ded to optimize its microstructure and performance, and to explore new application areas.Another important factor to consider is the composition of the copper-graphite composite material. The ratio of copper and graphite, as well as the addition of other elements, can significantly affect its tribol
30、ogical properties. For example, increasing the graphite content can enhance the lubrication performance, but may also decrease the mechanical strength of the material 17-18. Therefore, it is necessary to balance the lubrication and mechanical properties according to the specific application requirem
31、ents.Additionally, the surface roughness and hardness of the sliding partners can also influence the tribological behavior of copper-graphite composite material. A smooth and hard counterface can reduce the wear and improve the lubrication effectiveness by enhancing the transfer film formation and r
32、educing the particle detachment 19-20. On the other hand, a rough or soft counterface may lead to severe wear and damage of the material.Furthermore, the working conditions such as temperature, pressure, and velocity should also be taken into consideration. Copper-graphite composite material can wit
33、hstand a wide range of temperatures and pressures, but excessive temperatures or pressures can cause thermal or mechanical degradation and reduce the performance of the material 21-22. Moreover, high velocity can generate more frictional heat and increase the wear rate, calling for effective cooling
34、 and lubrication measures.In conclusion, the tribological behavior of copper-graphite composite material is influenced by various factors, including microstructure, composition, surface properties, and working conditions. A comprehensive understanding of these factors can guide the design, selection
35、 and application of the material, and optimize its tribological performance.In addition to the factors discussed above, other factors may also affect the tribological behavior of copper-graphite composite material. For instance, the manufacturing process can influence the microstructure and properti
36、es of the material, which can in turn affect its tribology performance 23-24. Various techniques such as powder metallurgy, casting, extrusion, and sintering can be utilized to prepare copper-graphite composite material with desired microstructure and properties.Moreover, the addition of other addit
37、ives such as solid lubricants, reinforcements, and surface coatings can also enhance the tribological properties of copper-graphite composite material 25-26. For example, the inclusion of molybdenum disulfide or tungsten disulfide can improve the self-lubrication ability of the material and reduce t
38、he wear rate 27-28. Similarly, the reinforcement of ceramic particles or fibers can enhance the mechanical and wear resistance properties of the composite material.Additionally, the surface treatment and finishing techniques such as polishing, hardening, and coating can also enhance the tribological
39、 performance of copper-graphite composite material. For instance, diamond-like carbon (DLC) coatings can provide a low friction and wear-resistant surface to prolong the service life of the material 29-30. Similarly, ion implantation or laser hardening can improve the surface hardness and wear resis
40、tance of the material.Therefore, it is crucial to consider various factors and techniques when selecting or designing copper-graphite composite material for tribological applications. A thorough understanding of the material properties and working conditions can help to optimize its tribological per
41、formance and increase its durability and reliability.Apart from the factors mentioned above, the lubrication conditions and environmental factors also play essential roles in the tribological behavior of copper-graphite composite material. The type of lubricant, its viscosity, temperature, and press
42、ure can affect the friction and wear of the material 31-32. For instance, in dry sliding conditions, copper-graphite composite material can exhibit high friction and wear due to the lack of lubrication. However, with the addition of a suitable lubricant, such as oil or grease, the friction and wear
43、can be significantly reduced.Moreover, the environmental factors, such as humidity, temperature, and chemical exposure, can affect the properties and performance of copper-graphite composite material 33. For instance, in high humidity conditions, the graphite in the material may absorb moisture and
44、lose its lubricating properties, resulting in increased friction and wear. Similarly, exposure to corrosive chemicals can cause chemical reaction and degradation of the material, leading to decreased mechanical and tribological properties.Therefore, careful selection of lubricants and consideration
45、of environmental factors are crucial in optimizing the tribological performance of copper-graphite composite material. Additionally, the design and operation of the tribological system can also affect the performance of the material. For instance, the selection of appropriate material pairings, surf
46、ace roughness, and contact pressure can affect the friction, wear, and heat generation of the system 34.In conclusion, the tribological behavior of copper-graphite composite material is influenced by various factors, including the microstructure, material properties, manufacturing processes, lubrica
47、tion conditions, environmental factors, and system design. A thorough understanding of these factors and their impact is necessary to optimize the tribological performance of the material in different applications.In addition to the factors mentioned above, the wear mechanisms that occur during trib
48、ological interactions also influence the tribological behavior of copper-graphite composite material. The wear mechanisms observed in copper-graphite composite material depend on the operating conditions, such as sliding speed, load, and temperature 35.One of the primary wear mechanisms in copper-gr
49、aphite composite material is adhesive wear, which occurs due to the transfer of material from one surface to another during sliding. This type of wear usually occurs at low sliding speeds and high contact pressures. Another wear mechanism is abrasive wear, which is caused by the presence of hard particles or asperities on the opposing surface. This type of wear typically occurs at high sliding speeds and low contact pressures.Moreover,
