Preparation method of diamond coating and prepared diamond coating, cutting tool

Abstract

The invention discloses a preparation method of a diamond coating and the prepared diamond coating and a cutting tool, and relates to the technical field of diamond thin films. The preparation method of the diamond coating comprises the following steps: using a nano-diamond suspension to plant crystals on a substrate with a positive / negative charge on the surface, and growing diamond by a hot wire chemical vapor deposition method to obtain a diamond coating; The charge of the nano-diamond particles is opposite to the charge on the surface of the substrate. The present invention utilizes the electrostatic adsorption crystal planting method to make the nano-diamond particles dispersed in the solution adsorb on the matrix structure, and this method can greatly increase the adsorption density of the nano-diamond particles on the matrix, nucleate at a high density on the surface of the matrix, and grow The final diamond coating has strong adhesion, long service life, low coating roughness and high precision. The tool deposited with this coating has a long cutting life and high machining accuracy.

Description

technical field [0001] The invention relates to the technical field of diamond thin films, in particular, to a method for preparing a diamond coating and a diamond coating and a tool prepared therefrom. Background technique [0002] With the rapid development of the industry, lightweight and high-strength materials have gradually become the mainstream. New materials such as non-ferrous metals and alloys, glass fiber reinforced plastics, graphite and ceramics are widely used in the industry. Common high-speed steel and cemented carbide The tools are difficult to perform the mechanical cutting of these materials. At the same time, with the successive advent of modern integrated system machining centers, mobile machining workshops, and computer-integrated manufacturing systems, machining is developing in the direction of high-precision, high-speed, and high-productivity cutting. high demands. Therefore, the development of various superhard cutting tools with excellent cutting...

AI Technical Summary

Problems solved by technology

However, the temperature required for hot wire chemical vapor deposition is relatively high. After the diamond film is prepared by this method, in the process of cooling to room temperature, due to the large difference in thermal expansion coefficient between the diamond film and the cemented carbide tool, it is easy to produce thermal stress. The resulting film-base interface bonding force is poor, and cracks are formed at the interface, which makes the diamond film easy to fall off during the cutting process

During the cutting process, the ratio of the failure of the film due to the shedding of the diamond film to the end of the tool life due to wear is about 10:1. It can be seen that the adhesion between the film and the tool seriously affects the life of the tool.

[0005] Most of the existing technologies use the method of intermediate layer or multi-layer film to alleviate the coating peeling caused by thermal stress

Patent CN101880866A discloses a method for preparing a diamond-silicon carbide-cobalt silicide composite intermediate layer for diamond coating on cemented carbide. The thermal expansion coefficient of silicon carbide in the composite intermediate layer prepared by this method is 5×10 -6 -7×10 -6 / K, and the coefficient of thermal expansion of diamond 1×10 -6 -2×10 -6 / K still has a large difference, and it cannot solve the nucleation density of diamond in the composite layer

Patent CN106835133A discloses a workpiece with a titanium diboride-diamond composite coating and its preparation method. The method uses titanium diboride as the intermediate layer between the hard alloy and the diamond film to block the formation of Co in the hard alloy. Diffusion can increase the nucleation density of diamond film, but the thermal expansion coefficient of titanium diboride is higher than that of diamond film and cemented carbide, so it is not very suitable as an intermediate layer for relieving thermal stress, and can only be used as an outer layer of Co in cemented carbide. diffusion barrier

Patent CN105483644A discloses a multi-layer diamond coating and its preparation method, coating tool, which grows micro-diamond, nano-diamond and ultra-fine nano-diamond coatings on the surface of the substrate in sequence, so as to relieve thermal stress and improve coating The bonding force between the layer and the substrate, but the diamond film prepared by this method is complicated and costly, and it needs to be deposited three times, and the quality of the diamond film is likely to decline during the process of changing parameters, resulting in many layers between layers. defect

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