With the development of technology, the surface properties of materials are becoming more and more demanding. The rise of various vapor deposition technologies in recent decades has made the research and application of surface engineering technology a leaps and bounds. These technologies not only achieve mechanical performance requirements, such as wear resistance, friction reduction and corrosion resistance, but also play a role in the field of functional materials related to the surface of electromagnetics, optics, optoelectronics, thermals, superconductivity and biology. Surface engineering not only makes low-cost metal materials have greater advantages in performance and efficiency, but also has become an important means to develop various new coatings and thin film materials, and has great application potential. With the improvement of the level of the machining industry, new requirements have been placed on tools. In addition to increasing the service life, it is also required to reduce the contamination during cutting, and use dry cutting whenever possible. When the cutting fluid cannot be completely eliminated, it is best to contain only the rust preventive agent and no organic matter, which can greatly reduce the cost of recycling. The variety of machine tool cutting tools and the working state characteristics at the time of use determine the difference in the choice of tool plating. Different from turning and drilling, the milling cutter should also consider the characteristics of its intermittent impact. Early development of the coating is mainly focused on wear resistance, with hardness as the main indicator. Such a coating represented by titanium nitride has a high coefficient of friction (0.4 to 0.6), and a constant friction between the workpiece and the workpiece generates a large amount of heat energy. In order to avoid the tool overheating and deformation, which affects the machining accuracy and prolongs its service life, cutting fluid is usually used. To solve the problem of reducing or eliminating cutting fluid, the tool coating should not only have a long life, but also have a self-lubricating function. The presence of diamond-like coatings (LC) has shown advantages in the mechanical processing of certain materials (Al, Ti and their composites), but after years of research, it has been shown that diamond-like coatings have high internal stresses and poor thermal stability. The three shortcomings of the catalyst effect between the ferrous metal and the SP3 structure shifting to SP2 determine that it can only be applied to the processing of non-ferrous metals, thus limiting its further application in machining. However, recent studies have shown that the hardness of diamond-like coatings (also known as graphite-like coatings) based on SP2 structure can reach 20-40 GPa, but there is no problem with the catalytic effect of ferrous metals, and the friction coefficient is very high. Low and good moisture resistance, can use coolant and dry cutting when cutting. Its life is doubled compared with non-coated knife. There is no problem in processing steel materials, which has caused coating companies and tool manufacturers. Great interest. Over time, this new type of diamond-like coating will find wide application in the field of cutting.
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