CVD金刚石薄膜在水润滑条件下的摩擦磨损性能研究
CVD金刚石薄膜在水润滑条件下的摩擦磨损性能研究【Abstract】 CVD diamond films have excellent mechanical properties and thermal conductivity. However, under water lubrication conditions, their friction and wear performance are greatly reduced. In this study, the wear behavior of CVD diamond films under water lubrication conditions was investigated by using a pin-on-disk friction and wear tester. The effect of different sliding speed and load on the friction and wear behavior of the CVD diamond films was studied. The results showed that the wear resistance of the CVD diamond films decreased significantly under water lubrication conditions, and the wear mechanism of the films was mainly abrasive wear and adhesion wear.【Introduction】 Diamond has excellent mechanical properties such as high hardness, high wear resistance and high thermal conductivity. CVD diamond films have been widely used in various industrial fields due to their excellent performance. However, when used under water lubrication conditions, the friction and wear performance of CVD diamond films is greatly reduced. This is mainly due to the formation of water film on the surface of the films, which reduces the contact between the film and the counterface, resulting in an increase in friction coefficient and wear rate of the films. Therefore, it is necessary to study the friction and wear behavior of CVD diamond films under water lubrication conditions to improve their performance.【Experimental】 The CVD diamond films were deposited on silicon substrates by using a hot-filament chemical vapor deposition (HFCVD) process. The pin-on-disk friction and wear tester was used to measure the friction and wear behavior of the CVD diamond films under water lubrication conditions. The friction coefficient and wear rate of the films were calculated by using the recorded load-displacement and friction force data. The surface morphology changes and wear mechanisms of the films were observed by using a scanning electron microscope (SEM) and transmission electron microscope (TEM), respectively.【Results】 The friction coefficient of the CVD diamond films increased significantly under water lubrication conditions compared with that under dry sliding conditions. The wear rate of the films increased with the increase of load and sliding speed. The wear mechanism of the films was mainly abrasive wear and adhesion wear. The abrasive wear was caused by the sliding of hard abrasive particles on the films, while the adhesive wear was caused by the bonding and delamination of the films due to the strong adhesion between the films and the counterface under water lubrication conditions.【Conclusions】 The performance of CVD diamond films under water lubrication conditions is greatly affected by the formation of water film on the surface of the films. The friction coefficient and wear rate of the films increase significantly under water lubrication conditions. The wear mechanism of the CVD diamond films under water lubrication conditions is mainly abrasive wear and adhesion wear. To improve the performance of CVD diamond films under water lubrication conditions, it is necessary to develop new lubrication systems or modify the surface of the films to reduce the adhesion between the films and the counterface.To improve the wear resistance of CVD diamond films under water lubrication conditions, various approaches have been proposed. One approach is to modify the surface of the films to reduce their interaction with water. Surface modification techniques such as plasma treatment, ion implantation, and chemical etching have been used to change the surface properties of the films. For example, plasma treatment with O2 or N2 gas can increase the hydrophilicity or hydrophobicity of the films, respectively. It has been reported that hydrophobic surfaces have better wear resistance under water lubrication conditions than hydrophilic surfaces. Another approach is to use different lubricants to reduce the interaction between the films and the counterface. For example, it has been reported that the use of ionic liquids or fluorocarbon-based lubricants can significantly reduce the friction coefficient and wear rate of the films under water lubrication conditions.Moreover, CVD diamond films can be combined with other materials to form composites with superior wear resistance. For example, CVD diamond films can be deposited on metal substrates, which can improve the wear resistance of the metal components under water lubrication conditions. The composites can also be formed by incorporating other materials such as nanoparticles or carbon nanotubes into the CVD diamond films. The added materials can fill the gaps between the diamond grains and enhance the mechanical properties of the films, which can improve their wear resistance under water lubrication conditions.In conclusion, the wear behavior of CVD diamond films under water lubrication conditions is influenced by multiple factors, includi