Deposition Of Diamond Silicon-Carbide Composite Film On YG6 Cemented Carbide Substrate

In recent years,diamond coated tools have been widely used,but their service life is short due to the current diamond coated tool film has poor bonding strength with the substrate,which makes the use cost higher.In order to further improve the film-based bonding force of diamond coated tools,the following explorations is made.In the calculation part,the residual thermal stress of diamond-silicon carbide composite film by HFCVD(Hot Filament Chemical Vapor Deposition)is studied.The finite element simulation(FEM,Finite Element Method)is adopted.The residual thermal stress in HFCVD diamond-silicon carbide composite film with five different structures are calculated and analyzed by finite element simulation software ANSYS.The X-direction stress at the interface junction is the main reference basis to evaluate the bonding strength between the film and the substrate.Simulation results show that the transition layer can alleviate the stress concentration level at the interface of the film-substrate interface.Among the five film structures,the composition gradient transition layer has the best effect of relieving stress,and at the same time ensures the hardness of the film surface.The composition gradient transition layer is the best performing diamond-silicon carbide composite film among the five film structures.In the experimental part,the effect of alkali treatment time on the film-based bonding force in the pretreatment of diamond film deposition is explored.The experimental results showed that the surface treatment with alkali for 10 min and acid treatment for 1 min was the best pretreatment process;The effect of methane concentration on the surface morphology of diamond was studied.The experimental results show that increasing methane concentration can refine the grain of diamond,but the quality of diamond is degraded;Then the influence of distance between filament and substrate on the surface morphology of diamond is studied.It is shown that the grain refinement of diamond is reduced and the quality of diamond is degraded when the distance is reduced;The last part of the experiment,the growth law of diamond-silicon carbide composite film was explored.The experimental results show that the ratio of silicon carbide to diamond in the diamond-silicon carbide composite film can be controlled by adjusting the distance between filament and substrate.Based on the law,four kinds of silicon carbide-diamond composite films were deposited,and then their bond strength is tested by Rockwell hardness tester.The test results showed that the pure diamond film had the worst bonding force.The gradient layer can improve the film-based bonding force,and the gradient component transition layer has the best binding force,and the experimental results are consistent with the simulation results.