Study On Slurry Of Photocatalysis Assisted Sharpening Diamond Tool

Diamond is a type of material with maximum hardness and minimum friction coefficient in the nature world.It has a wide application prospect and huge market potential as the third generation simiconduct material to be an emphasis on the new generation information technology,combining many excellent properties such as mechanical,optical,thermal and electrical.With the rapid development of synthetic diamond industry in China,the synthetic diamond cutting tools are widely used.However,the prepared diamond crystal is oversize and the surface roughness is not compatible to directly use as a diamond tool.Besides,the high hardness and chemical stility of the diamond will bring tough challenges to the surface processing with super smooth,high precision and low damage.Therefore,based on chemical mechanical polishing of diamond,a new diamond polishing method is proposed integrating the photocatalytic oxidation technology,which aims to build an effective diamond tool machining method and solve the current problems of polishing liquid effumability,equipment corrosion and environmental pollution in chemical mechanical polishing.The main research about the photocatalytic oxidation assisted polishing diamond tool slurry includes the following:?1?The diamond grinding method assisted by photocatalysis is proposed by analyzing the photocatalytic oxidation mechanism;the photocatalytic assisted polishing test platform is built and Merc-1000 mercury lamp is selected as the output light;the REDOX potentiometer is selected to be as a characterization of the slurry;the metalloscope and the atomic force microscopy are selected as the material testing device.?2?Aiming to the different selection of the catalyst,oxidizing agent,abrasive,and the ph regulator,the three types of the slurry characterization method is proposed.By the redox potential and conductivity characterization test,it is concluded that the solution oxidability of TiO₂ is the best and the solution of P25 TiO₂ is the most stable,and the photocatalytic activity is the best when the dosage of H₂O₂ is 2³ml and pH value is 3.The methyl orange is degraded by photocatalytic and the color is totally faded after 1 hour,which validates the oxidability of the slurry.The characterization test of the silicon wafer polishing materials is established to validate the polishing feasibility and the result can be obtained by 7 slurry comparison.The best slurry is composed of TiO₂?P25?+ H₂O₂+ UV-light+SiO₂+H+,and the material removal rate is 5.9mg/h.The surface morphology is the best.?3?The slurry validation test of various diamond tool is established.The ultra smooth step surface is obtained in the photocatalytic polishing of the membrane,and the surface roughness reduced from Rz387.6?m to Rz47.131?m.The polishing quality of P25 is the best by polishing the CVD diamond with different catalyst slurry,and the final surface roughness is Ra0.399 nm.The material removal rate reaches 0.012mg/h in diamond polishing with high temprature and high pressure.The polishing trajectories simulation is established by Matlab and the reasonable speed of the polishing disk is 60r/min,and the speed of the sample disk is 31r/min.The flank surface and the blade of the diamond tool with high quality can be obtained combining the above process.The holes with high oxidability on the surface of TiO₂ is grown under the UV-light by analyzing the XPS energy spectrum analysis,and H₂O will be decomposed by these holes in the acid environment into hydroxyl radical with high oxidability,and the hydroxyl radical reacts with the diamond into oxide.