Research On Fabrication Of Surface Patterned CVD Diamond Coating With Solid Lubrication Phase

CVD diamond has excellent properties,and has broad application prospects in the fields of tool coating.However,due to the strong chemical activity with iron and titanium and the low adhesion between coatings and substrates,the coating shedding and tool wear are accelerated,which restricts the application of CVD diamond coating tools in cutting steel and titanium alloy.Surface texture and solid lubrication can effectively improve the friction state and enhance the cutting performance of coated tools.Therefore,in order to improve the performance of CVD diamond coatings,the design and process of the pre-texture and the fabrication and evaluation of solid-lubricated textured CVD diamond coatings were carried out in the thesis,which had significant application value for the design and manufacture of textured CVD diamond coatings.The main research contents and achievements are as follows:1.Parameters of the pre-texture were designed,and patterned substrates were fabricated.The suitable substrate material was selected according to the process requirements and material properties.The friction reduction principle of surface texture under different friction conditions was analyzed.The parameters of pre-texture were designed,modeled and processed.High quality substrates were obtained by ICP etching.2.The process of CVD diamond coating deposited by HFCVD was studied.The nucleation and growth process of HFCVD and the factors that affect the deposition quality were both analyzed.The comparison experiments of deposition quality,related to substrate surface pretreatment and carbon source concentration,temperature of substrate and deposition time,were carried out.The deposition conditions and process parameters were optimized.3.The deposition experiments of textured CVD diamond coating were carried out.The compact and uniform textured coatings with smooth surface and good shape were obtained.The dry friction coefficient against steel ball was tested.The influence of texture parameters on the friction coefficient and the optimized texture parameters were obtained.4.The preparation and lubrication properties of solid lubricated composite textured coatings were studied.The deposition principle and factors of magnetron sputtering were analyzed.The deposition experiments of MoS₂ were carried out on textured CVD diamond substrates.The compact and uniform composite textured coatings were obtained.The friction reduction and lubrication effects of texture parameters under different durations were analyzed,and the corresponding optimized texture parameters were obtained.