Study On Scratching Simulation And Tribochemical Performance Of Silicon Carbide

Silicon carbide (SIC) ceramics have high stiffness, high abrasion resistance, highbrittleness and low fracture toughness properties. To obtain high surface quality and lowsurface and subsurface damage, it is need to be machined in ductile regime.Tribochemical Polishing is a kind of new technology for ceramics to realize smoothsurface without damage, material is removed by chemical dissolution and the frictionrush between the tool and the polishing disk to dissolve small peak contact placepriority, so as to end up with no defect and low residual stress smooth surface. So thesetwo aspects of research on ultra-precision processing of SIC surface is of greatimportance.Firstly, through the nano indentation experiment we got the load-deep curve ofsilicon carbide material, and mechanical performance parameters such as elasticmodulus and hardness. Also the fracture toughness of material is obtained bymicrohardness test, laid a foundation for the accurate description of silicon carbidescratching simulation of elastic-plastic material performance. And then, establishedfinite element model of single diamond scratching of silicon carbide, research on chipformation mechanism, and the change rule of the cutting force and normal force withcutting depth and cutting speed varies. Simulation analysis has important guidingsignificance to determine the SIC ductile processing parameters in the research.Secondly, research on the chemical properties of silicon carbide ceramic materialsthrough friction experiments.(1) Design reciprocating friction and wear experimentmachine, so as to increase the material removal rate and surface quality as the goal,optimize the processing parameters of TCP. Finally in the stress of2N, speed of0.02m/s experimental conditions could at the same time get high material removal rate andgood surface quality.(2) Respectively for four kinds of water-based polishing fluid,with the optimize process parameters to do TCP experiments, the composition ofpolishing liquid on the material removal rate and surface quality are studied. Theexperimental results show that high material removal rate and good surface quality canbe obtained by20%NaOH solution, and can achieve a global plane in the siliconcarbide wafer processing.(3) For frictional chemical removal mechanism of siliconcarbide materials analysis, established a frictional chemical removal model and materialremoval rate model. And analysis the influence law of pressure and velocity on siliconcarbide material removal rate, the analysis results show that the pressure increasedenhanced mechanical action and speed increased enhanced chemical action.