The Experimental Study And Design For The Preparation Of Diamond Coating For Multi-Function Hot-filament Chemical Vapor Deposition

Diamond has many excellent properties in mechanics,electricity,heat,optics and so on,so it has a wide application prospect in many aspects.As for the natural diamond is scarce and difficult to be widely used.The hardness,thermal conductivity,elastic modulus and other physical properties of diamond films prepared by chemical vapor deposition(CVD)are close to or achieved the properties of natural diamond and the problem of scarce natural diamond content will be solved.However,because of the lack of study on the design and manufacturing technology of diamond coating equipment,the advantage of chemical vapor deposition technique in the preparation of diamond coating.In this thesis,the design and manufacturing technology of hot-filament CVD diamond coating was taken as the research object,the problems such as vapor deposition process parameters were researched.Based on the technology characteristics of chemical vapor deposition process,a set of multi-function hot-filament gas phase deposition equipment for diamond coating deposition was designed and manufactured.The equipment mainly consists of water-cooled vacuum chamber,gas circuit system(with blowing gas path),2d(plane)sample table(water cooling,rotatable),3d(solid)sample table(for internal hole deposition),cutting tool sample table,sample water cooling system,sample bias system(for plating inner hole and plane sample),hot-filament system(hot-filament rack can lift),hot-filament heating control power supply,heat shield component,control system(with PLC and color liquid crystal touch screen),vacuum unit and vacuum measuring system.According to the rystallization mechanism and adhesion mechanism of diamond film particles,the influencing characteristics of external deposition parameters such as pressure,methane/hydrogen concentration and substrate temperature on diamond growth rate,diamond morphology and the quality of the nuclear.The CVD diamond coating cemented carbide tool were manufactured by the self-designed equipment.The scanning electron microscope was used to observe the diamond coating tool surface appearance and the diamond tools were compared with exotic blades.The results showed that the diamond growth rate showed linear growth with the increase of deposition pressure.5KPa is the optimum pressure of this equipment according to the particle morphology and Raman analysis results;The growth rate of diamond has been greatly improved by the increase of concentration of methane due to the transformation from micron diamond to nano-diamond.The 1.5%methane concentration is a better choice.The optimum sedimentation temperature of CVD process around 870 ?.The performance of the cutter reaches the level of foreign cutter and small batch production was carried out that laid an important foundation for the basic research of CVD diamond coating tools and the industrial application of CVD diamond coating tools.