Study On Single Crystal Diamond Processing With Sol-gel Polishing Film

Single crystal diamond has excellent physicochemical properties such as high hardness,wide band gap,high thermal conductivity,and high chemical inertness.As a semiconductor material,diamond occupies the most important position in the fields of electro-optic,machinery and so on.At the same time,the stable physical and chemical properties of single crystal diamond for ultra-precision processing bring certain difficulties.This work proposes single crystal diamond(100)and(111)plane has been polished by SG polishing film.Meanwhile,the processes and mechanism of material removal has been explored.Comparing the processing effects and mechanism of action by mechanical and chemical polishing way,to increase the machining efficiency and improve surface quality,to achieve the surface of the low damage.In the experiment,the smooth surface can be obtained on the surface of diamond(100)plane with low pressure and mild processing.The results showed that the surface roughness of hardest single crystal diamond(111)plane reached 1.088 nm and the local surface roughness was 0.70 nm.In addition,the material removal mechanism of diamond surfaces is mainly the physical and chemical reaction between workpiece and abrasive by SG polishing film.The mechanical action of the(100)crystal plane is mainly scratch and squeeze and the(111)plane is crunch cleavage removal.At the same time,the phase transformation is mainly converted to amorphous carbon and graphite.In this paper,on the basis of the semi-solid abrasive machining added mixed abrasive and chemical reagents,compared to(100)plane effect and mechanism of action in MP(Mechanical polishing),MCP(Mechanical chemical polishing)and CMP(Chemical mechanical polishing)processing methods,in order to improve the surface quality of diamond in the finishing stage.Mechanical chemical polishing can effectively increase the processing efficiency,and the removal rate at 25.5nm/min,significantly better than the other two processing results.The solid phase reaction between diamond surface material and silicon carbide abrasive was induced by mechanical action.It can effectively promote the amorphization and graphitization phase transformation of diamond.Chemical mechanical polishing is beneficial to the removal of chemical corrosion on the surface of diamond.Furthermore,the mechanism of mechanical removal on the diamond surface was verified by the morphology of the scratch.The subsurface damage forms and damage scales of diamond(100)plane after MP,MCP and CMP were investigated.The damage was mainly in the form of amorphization,dislocation and lattice distortion in 2.0-3.3nm damage scale,compared with other processing methods,the subsurface damage scale formed by mechanical chemical polishing method is the largest,about 3.3nm.It is also a match to the larger material removal rate found in this study.